+1 for all of Yoko Kanno's work on Cowboy Bebop. I'd also love soundtracks for Ghost in the Shell, Akira, Redline, and the collected work of The Pillows (FLCL.) All would get heavy use in my playlists.
But it's neat that they have Castlevania: Symphony of the Night available:
I have a playlist that has nightcore, japanese, and anime music in it. Spent the time finding all the songs. Im not sure what playlist number it is (i have 15) but it is public if that is what you are looking for.