Anime Music and OST's

I thought that this forum could do with a thread where people can talk about the music sound tracks off various anime series.

To start with I found an excellent track called "Gabriel Fauré - Requiem - Pie Jesu", You'll recognise it as the Opera that is played at the start of Gantz (When the gantz appears). Unfornaturely it is only the midi version.

http://www.sendspace.com/file/2sm0w6

Does anyone know where I can buy or download the real one from?

I own the following soundtracks:
Trigun
Gungrave
FLCL
Rahxephon
Hellsing

And I'm currently looking to buy Outlaw Star's.

rurouni kenshin