NHL-Tampa Bay Lightning. Like most people I didn't care about hockey. In 93 I went to my first game and ever since I was hooked. Chances are most people who don't like hockey have never been to a game. So I like the Lightning because they were my first experience with the sport.
College football- Miami Hurricanes. Back in the mid to late 80's they were the bad boys of the game. I remember one game they had against Georgia Tech I believe and at the end of the game they had a bench clearing brawl. Most of their games back then would end with a fight of some kind. I especially like it when they beat up on FSU.

Not to mention they could back it up with the way they played on the field.
NFL- Bucs. Only because I would like to see them do well. They had so many crappy years and since they are they home team you have to pull for them sometimes. Unfortunatly it looks like their back to being the doormats of the league.