I might give Warriors Dolph Lundgren (he did play Adam of Eternia, and He-Man has tank written all over him) but that is still not enough to top ol' Chuckers.
I'm going to pro-actively give monks David Carradine, which is a certain level of cool, I will admit.
Rogues - Kurt Russel (ala Snake Plisskin.)
Paladins - Clint Eastwood.
Warlock - um, Charlie Sheen, geez, you should have seen that one coming.
Death Knight - maybe Steven Segal, maybe. I'm kind of reaching on this one.