My favorite leagues might be the lower minor leagues. I could get all righteous and talk about how pure the game is at that level - players don't make a lot of money and they haven't been jaded by fame, etc. And that probably has something to do with it. But really, it's just a different feel. It's a relaxed event, with smaller crowds, lower prices, a local feel, and less hype (think: sound and video effects, walk-up music, and so on).
I love MLB games, but I think I'd prefer to have a season ticket to a smaller A- or AA-level team. I seriously considered buying season tickets for the Gwinnett Braves while I was living in Georgia (money was the only real issue) - when there was discussion of a rookie level team around Atlanta about seven years ago and my town held one of the stadiums they were going to use, I had immediately decided I would be a charter season ticket holder. Too bad that never followed through.
Anyway, despite my interest in the minor leagues, I've never really collected minor league sets. But that doesn't mean I have no interest in them.