MLB: The Reds, of course. In the AL I root for the Indians (I grew up in Cleveland). Still hope for an All-Ohio WS although I'd be pulling for the Reds.
NFL: The Bengals. Really, really, really disliked Art Modell when he fired Paul Brown. Loved it when PB started the Bengals, visited PB's home in Cincinnati and met him and his wife several times, class act, both of them.
NBA: Don't follow it much anymore but still wish the Cavs well. Was at their first home game, owned stock in the team and Bill Fitch, their first Coach was my colleges' coach my senior year. Not to mention that they were a customer of mine at the time plus I had gone to college with several of the front office people.
College Sports: Root for my alma momma, Bowling Green but, since they don't get the pub of the big schools, it's a little had to follow sometimes.
The rest of the sport picture has grown hazy because, it seems to me, as you get older, sports simply don't have as much importance to you as they did when you were young.