For Rohm, my exiled paladin-turned-fighter, Nathan Fillion.
For Nym, my half-drow/half-high elf rogue - It'd be easy to say Luke Goss. His portrayals of Nomak and Nuada fit the dark, messed up character.
And for Quinn, my human rogue, Probably Mark Wahlburg. Broody, quick to anger, and not the brightest of people.