i really like this artist, he did hellsing's raid and ruin ost, and darker than black's ost.
it's the kind of ost that make me says while i watch the anime:
but wait.. the soundtrack is awesome !
if you want more, here's some of my favorites:
-http://www.youtube.com/watch?v=fNHnxDdORE4 for a huge guitar solo
-http://www.youtube.com/watch?v=nbc9IE8VU2M&list=PL9730E0AF1925D5C2 for bassists like me
and i'm sure you'll be able to find more on youtube if you like it.