So, I pre-ordered a copy of the Black & White Soundtrack just after importing my copy of Black. And from what I've heard so far, it was money well spent.
I've got four badges so far, so I haven't heard everything yet, but highlights so far include:
Route 2 & 3: This is one of those songs that you just can't get out of your head, no matter how hard you try. It's just so perky!
Battle! Wild Pokémon!: Probably my favourite battle music after Johto's wild Pokémon music. The special Pokémon variant for wild double battles and special encounters is also pretty awesome.
Battle! Gym Leader - Last Pokémon!: SO MUCH WIN HERE. How do you make the fact that you're kicking a gym leaders' *** even more awesome? You set it to an incredibly heroic version of the Pokémon main theme, that's how. If this music doesn't get your adrenaline flowing, nothing will.
I can't really comment on starting town and Route 1's music, as I didn't really spend much time in those places. Once I earn the Fly HM, I'll go back and have a proper listen.