Im pretty open to trying most games and some of the sports games have become my favorites even though I don't like sports in general. Everyone should try Baseballs Stars 2, Windjammers, and Neo Turf Masters - especially with friends and some beer.
Games I have never bothered playing though include most of the puzzle games, because I already have Puzzle Bobble and Magical Drop 2 and I can't imagine most of the other games are really THAT different.
Fighting Fever and Karnov's Revenge don't look great either, so I skip those games.
Some of the early games like Ninja Combat and Cyberlip just don't look good at all, for the price anyway. Maybe if I scored them for $30 I'd give it a go, or a conversion.