Speaking of anime soundtracks I like (that's the opening theme for Gantz), here's some more.
RIP Nujabes, you left this earth too soon...
The guy who made the opening theme for Berserk also did the soundtrack to Paprika and Paranoia Agent. He's got a truly unique sound.
I fell in love with the FLCL soundtrack right away when it had just come out, and still love The Pillows.
This one is funny because first of all
an anime opening used a song by Duran Duran, and on top of that they had to change the song for the American release due to copyright shit or something...