CHIME NOISES INTENSIFY
I wouldn't say it had the best since each generation had it's good and bad, but BW's soundtrack was really good. I liked Accumula town, Icirrus city, Ghetsis's theme, the dreamyard, and the rival's themes.
I can't answer the BW vs B2W2 question as I haven't really heard any of the music. I think the music was less "inspired by something" and more of a new take on old things. (a desert, the first route, rival battles, the ice town etc) If it had to be inspired by anything, it was definitely inspired by the environment. (as it always is I guess lol) Nimbasa's music is for Nimbasa only, it wouldn't fit in say Driftveil or Castelia. I felt they did an exceptional job with that in these games.
I'd have to say Icirrus's theme at the moment, but it changes. I wouldn't say they have the BEST music in all the land, I mean, the Mario bros theme is pretty damn good, and I don't even play Mario too often so...
Also, some of the Harry Potter games have some rockin' beats. ^_^