And here they are, in no specific order (well, in order of which I remmeber them). Please feel free to add your own, and I'll update when I think of some more. Perhaps if we get enough links, the admins could stickify this.
Led Heavy - A highly stylized err.. stlye. Check out "Skottie" in particular
Josh Nizzi - The concept artist for RF2, he's got some really cool stuff
Chris Bachalo - Worked on X-Men for a while, then did his own series, Steampunk.
Joe Madureira - He's THE man. X-Men, Battlechasers and now he's doing stuff for the games industry.
Feng Zhu - Worked for Battle Realms, and has some really neat stuff (especially vehicles and such)
Falcoon - Some Japanese guy, I just stumbled across his art. Very nice, though a bit strange. Characters, and plently of them. Pro style.
Onixan - Site is being updated. His art is very nice, it reminds me

of Joe Mad's stlye. Worth checkig back every once in a while.
Archangel Studios - Creators of the hit comic book The Red Star, these guys mix hand-drawn and CG art beautifully.
Expect more, since I usually tend to remember things after the fact.