If I had to choose...
My favorite soundtracks in Pokemon games all reside in Pokemon Colosseum / XD. Though I hate Colosseum with a passion, it has one of the best songs I have listened to, ever.
@Soarin: There's no hax in pokemon.
@Soarin: Crits are supposed to happen.
@Soarin: Flinches are supposed to happen.
@Soarin: Paralysis is supposed to happen.
@Soarin: Deal with it.