Yes I know, stupid thread. Bare with me, I'm bored :(.
Franky: Roadhouse Rock, Blues, Dick Dale
Usopp: Reggae
Sanji: Smooth Jazz when he's alone; Barry White when he's with the ladies
Zoro: nothing
Chopper: whatever Usopp's into
Luffy: Techno
Robin: Enya, traditional folk music
Crocodile: Classical, Baroque (really!)