Lets see, I love Ice Hockey, and the NHL games tend to be pretty good - The mechanics and controls of recent NHL games are actually pretty damned good.
I dislike Association Football, however my "bros" (hate that terminology, but the lads I play FIFA with pretty much fit it) and I are pretty into gathering round and playing FIFA against one another, and I enjoy the Championship/Football Manager games as I enjoy the stats, formations, tactics, etc. etc. side of it all.
I also have been known to invest in Rugby Union and League Games - Rugby League Live and Live 2 are pretty poor, but I feel that I need to buy them in order to encourage the eventual creation of a decent Rugby League game. So far the only decent Rugby Union game I've played was Jonah Lomu Rugby way back on the PS1 - I'm less bothered about getting a good Union game as I prefer League (and I think a well done League game will make for a better video game), but it'd be nice to see eventually.
I don't buy every single iteration of these games (indeed I don't buy FIFA at all - I play friends copies). With NHL I buy once every 4-5 years or so, and Football/Championship manager whenever the gameplay actually gets updated significantly (Though lets be honest, Champ Manager 97/98 has never been topped)