Teams that should be good.

Before I get to my main point, let me say one thing about the Lebron James sweepstakes. I hope, with all my heart, that he leaves Cleveland and goes someplace else.
I can't tell you how utterly absurd I find the Cleveland "pitch" to Lebron. Essentially, the Cavaliers have said "come back to us, or you'll have blood on your hands." Their entire sales pitch to this man has been to try and guilt him into coming back, as if Lebron owes Cleveland or the Cavs something.
To me, Cleveland is now that mentally unstable girlfriend (or boyfriend, depending on who is reading this:) who senses the breakup is coming, so threatens to do bodily harm to his or herself if it does happen. The relationship continues, not because both sides want it, but because one side is afraid of "hurting" the other.If Lebron returns to Cleveland, I fully believe it will be because, and only because, he has been convinced he "has to do it" for the sake of the town. What a despicable way to try and appeal to someone.
Obviously, they can't appeal to their roster, or their ability to make moves because, well, they don't have a great roster or the ability to make moves. They also don't have a city that has ever shown an ability to not only build a championship team, but sustain such a team. So, when all else fails, try and make the person feel so bad about leaving, they end up staying. You know how long that works? It works right up to the point where guilt turns into resentment.
I have wanted to see Lebron head East because, if he played for the Knicks or the Nets, it would make the NBA a whole lot more interesting for me. I can't really tell you that, if the Knicks trot out Amare Stoudemire and Tony Parker next year, along with Mike Miller, that I will suddenly be looking into season tickets.
But, after hearing how pathetically desparate the Cavs pitch sounded, and how they seem to be the only team to use guilt (and also the only team seemingly willing to disparage other teams and their officials) I hope he goes anywhere else. Sign with New Jersey, Knicks, Chicago, Miami, heck, even the Clippers. Just, don't go back to Cleveland, Lebron. Don't let the NBA equivalent of the psycho girlfriend win your services.

Okay, enough of my rant.
The Lebron thing got me thinking about teams looking for a new start. See, the Knicks are a team that has been down on its luck for a very long time now, yet is an essential part of the NBA landscape. The Knicks have the history, the arena, and the fan base. What they haven't had is the success.
So, I began to contemplate which teams are in most need of a turn around in each of the major American sports. If I sat Roger Goodell, David Stern, Bud Selig, and Gary Bettman down in a secret room and asked them "which teams would you most like to see back on top" I think they would all have a list of teams.
For this post, I have limited it to the two franchises per sport I believe are most important to the league, and more in need of improvement (along with some honorable mentions).

NBA

1.) New York Knicks - The Celtics are good and should be at least for a few more years. The Lakers are at the top of the league. The Bulls are up and coming and could improve dramatically this offseason. The Mavericks always seem to be one break, or one personnel move away from being a top team.
The NBA has had a revival of sorts lately because a.) for the first time in years their young, talented players have been interesting and charismatic (and relatively free from any off-the-court problems) and b.) they have some very good teams in large markets.
Yes, the NBA is star-driven, meaning that they don't necessarily have to have their big market clubs succeed in order to prosper. However, despite the fact that Tim Duncan is one of the all-time great players in league history, and Dwight Howard is as exciting a young player as we have seen in years, the league ratings, especially in the playoffs, have been hurt by having smaller market clubs dominate.
That's why, despite what David Stern might say publically, it is hard to believe that, privately, he isn't rooting for the Knicks to come up winners in this free agent sweepstakes. Cleveland is a nice city and all, but the NBA has survive quite nicely over the years by having a less than competitive team in that area, as has every other sports league. Let's face it, few, if any analysts have ever uttered the words "the league could really use a big-time team/player in Cleveland."
If Lebron James were to defect to New York, people would lament the death of basketball in the Cleveland area, and villify James for "taking the money" in New York. However, after a few weeks, it would become clear that everyone in the league was doing hand stands.
New York is the biggest market in the world, Madison Square Garden one of the most famous in sports, and the Knicks are one of the teams, even after years of futility, that springs to mind when talking about the NBA. Having exciting games in MSG come May and June would be a huge boon to the league. You can have your Oklahoma City's and San Antonio's and Utah's playing top basketball, as long as your big markets are also at the top. The league needs the Knicks and, for their sake, hopefully they get a nice Fourth of July present this season.

2.) Philadelphia 76ers - It hasn't been that long since the 76ers were a playoff team, but it feels like it. The team made the playoffs in the 2004/05 season, but were swept out by the Detroit Pistons. Since then, and the trade of Allen Iverson to the Denver Nuggets, Philly has been devoid of basketball excitement and, just as important, devoid of any big-time players.
Philadelphia, even though they have not won a championship in many years, has been the home to some of the greats of the game. Wilt Chamberlain was a 76er, as was Moses Malone, as was Charles Barkley, as was Allen Iverson. These are not just nice players who put up good numbers, these are, all of them, hall of famers who helped shape the league at different stages of its maturation.
Having the 76ers struggle now for the league is somewhat like having the Celtics struggling, as they did, a few years back. Now, the C's are one of the two signature franchises in the sport, so having them on track is of utmost importance, but getting the 76ers back up to speed would certainly help as well.
We will see whether Evan Turner, Philly's most current draft pick, helps to rebuild the franchise or if he turns into a nice piece to the eventual puzzle, but the NBA is certainly hoping that, in the next few years, there is, once again, excitement for basketball in Philly.

Honorable mentions - Indiana Pacers (not a big market, but nothing says basketball like the state of Indiana), Portland Trailblazers (well on their way to being a contender again), New Orleans Hornets (after the success of the Saints in the NFL, no doubt the NBA would love to see its product turn into a success in the Big Easy).

NFL

1.) Oakland Raiders - We all know that the league still hates Al Davis. There are a bunch of former coaches and players who hate Al Davis. There is a good chance that God hates Al Davis. However, for the biggest, most successful sports league in perhaps the world, having a bad team in the Los Angeles/California Bay area is not good.
The Raiders are one of the most marketable and recognizable teams in the NFL. That skull and bones logo, by itself, is enough to ship a few million jerseys and hats. Yet, since John Gruden left and Rich Gannon retired years ago, the Raiders have become a laughing stock. Their draft picks have been utterly useless and the latest disaster, JeMarcus Russell, joins Ryan Leaf as perhaps the worst draft pick of the last 30 years. There might a little excitement now that the Raiders grabbed a decent quarterback, Jason Campbell, who might bring stability to that offense, but they still seem a long way from being major national contenders.

2.) San Francisco 49ers - What is amazing is that, when I contemplated the teams to include on this list, a good amount came to mind, which really tells you how teflon the NFL has become when it can thrive on teams like the Indianapolis Colts being a top draw. For the NBA I went East-Coast centric, here is is West Coast.
The 49ers might make the jump back into promience this season but, for a team that went from Joe Montana to Steve Young without missing a beat, and dominated the league for more than a decade. Now, they have to find a way to turn Alex Smith into a top quarterback and get their offense running smoothly. It might end up happening this season, but the NFL would sure love some exciting games in Candlestick in the near future.

Honorable mentions - Washington Redskins (this was my other obvious choice to make the top two, but I went with the 49ers instead), Chicago Bears (were in the Super Bowl a few years later, so avoid top two consideration, but still a team looking for a return to dominance), Miami Dolphins (they have been a playoff team a few times here, but haven't been a franchise challenging for a title in many, many years).

MLB

1.) Chicago Cubs - There is no stranger team in sports than the Cubs. Think about it; their entire history is one of losing. They are the Clippers or, before recently, the Arizona Cardinals of the NFL. They are a team going on 102 years of futility.
Yet, they are one of the most popular, and important teams in baseball. They, along with the Dodgers, Yankees, and Red Sox, are the team you think of when major league baseball is mentioned in passing.
If the Cubs could ever become a team challenging for a title every year, what a boom that would be for MLB. The interest in the team is already there. How much more would it shoot up if they were actually good?
MLB did, in my opinion, a horrid thing a few years back when it essentially blocked Mark Cuban from buying the organization. Cuban, the owner of the Dallas Mavericks, has proven to be one of the best business men in sports, a players kind of guy willing to spend to help a team win and, ultimately, make himself money. Is there any doubt Cuban would have turned the Cubs into a winner?
Instead, the Cubbies are left out to dangle with another "corporate" ownership group which is likely to run the team with a constant eye on bottom line.
What a shame.
The Red Sox got their championship after nearly 100 years of futility, as did the White Sox. The last kid on the loser block remains the Cubs. Baseball would love to see them get off the hump.

2.) Baltimore Orioles - Couple of teams to choose from for the second selection here, but I am going with the Orioles for a couple of reasons. First, they have a great baseball town, one of the best in the sport. Second, they still have one of the best ballparks in baseball that, when the team is good, will be sold out every single time. Third, they are in a market that should support a team producing a high payroll. Fourth, this is a team with a lot of history.
There are certain teams in baseball that, in my opinion, are in a desparate need of relocation (Rays, A's), but the Orioles could be easily successful right where they are. They are a product of horrid management and decision making and the people of that terrific baseball season deserve a lot better.

Honorable mentions - Kansas City Royals (the years of George Brett seem a long time ago and, despite their inclusion in the small market discussion, should be able to support a much better team), Pittsburgh Pirates (17 years of futility, but a good baseball town, great park, and a tradition of winning), Seattle Mariners (not a team you think of as being one of the traditional powers, but another team in a very good market, great city, great ballpark, great fanbase, and one that could easily have consistent success if run correctly).

NHL

1.) New York Rangers - I will readily admit that this is the sport where I have the least historical knowledge, but it doesn't take Bobby Ore's son to know the Rangers don't exactly have a stacked trophy case when it comes to Lord Stanley. Yet, as 1994 showed the world, the Rangers being a top team and winning can do wonders for the NHL as a whole.
Also, for a sport desparate to grow its product, not having the largest market in America is not something easily overcome. The NHL needs New York in play in order to kick start any emergence. That probably won't happen with the Panthers or the Ducks leading the way.

2.) Edmonton Oilers - I know they went to the finals in 2006, but it has been 16 years since the last time they had reached that stage, and it has now been 20 years since the team Wayne Gretzky made famous in the late 70s, early 80s won a title. NHL hockey is as much, or more Canada's game as it is Americas, and having a top teams in that part of the world is important to the league's overall success. They need big markets in America, and their Canadien teams to be good, and the Oilers are one of those teams that has tradition and fan passion. Having them return to the point where they routinely challenge for a title would be nothing but good for the league.

Honorable mentions - New York Islanders (Long Island's only team has tradition and brings with it parts of New York which, as already explained, is important), LA Kings (Gretzky's second home, would potentially bring the LA market).

(Note: only went with two because some of the leagues most important teams, such as the Boston Bruins, Montreal Canadiens, Philadelphia Flyers, and Chicago Blackhawks, all had big runs in the playoffs this year, so it was impossible to rate them as teams that "need to improve.")