If you liko Yoko Kanno, then definitely check out the soundtrack to Sousei no Aquarion. The show itself is average, but the music: Oh my god.
She teams up with the Warsaw Philharmonic Orchestra and the Warsaw Chorus again (she did Escaflowne with them previously) and it makes for some really amazing, apocolyptic music at times. Has a couple of techno-type tracks, the J-popish intro songs (near the end of one of the 2 OSTs, the first intro song is sung in english), and some lighter music.

RahXephon's soundtrack is great too. The opening is done by Kanno and Maaya Sakamoto (who voices one of the main characters), and the rest of the soundtrack is quite good, though I can't remember who did it all.

Koichi Sugiyama (Dragon Quest) makes some darn good music too. DQ8's orchestrated soundtrack has some beautiful stuff.