For finding similar artists I've been using
http://www.last.fm/music
This site isn't the best since it bases it's results off everyone using the website and for some of the similar artists it will give you, well...some have absolutely nothing to do with the artist you searched. But they give percentages as to which bands relate the most so it's still useful to a degree.
Annnnnd as for some bands goin by your tastes...
Slayer, Mastodon, Isis, High On Fire, Ill Nino