For battle scenes you couldn't do much better than...
*brandishes Black Mages album* THIS!
To anyone not in the know: The Black Mages did the reworking of One Winged Angel (the Sephiroth fight theme) in FFVII:AC. Although that song itself is actually very good, I prefer stuff like Maybe I'm A Lion as regular battle music.
Oh and Blur's Song 2 is good too