He's got the voice, and the build for it. You may never see his face, but I think Jeffrey Dean Morgan could handle it.Runner Up: Karl Urban
#8 on The Hottest Men Over 40
#1 on Batman Fantasy Castingsee more on Jeffrey Dean Morgan
CortanaThe starship AI that won the hearts of geeks everywhere, should be played by an actress that has done the same. Feisty and intelligent while also being vulnerable, it was a match made in heaven. Plus, if made right we'll get to see a weird CG body scan naked version of Evangeline as Cortana.
Also Rankedsee more on Evangeline Lilly
Gunnery Seargent BuckWhy mess with a good thing. Let's include ODST Buck in the mox and cast the man who played him in Halo 3: ODST.
#24 on Master Chief Fantasy Castingsee more on Nathan Fillion
Michael 'Mickey' Crespo and the voice of the grunts.Alan Tudyk voiced marines in the origianl games and Mickey in ODST. I say bring him into the movie and also have him work a little over time providing voices for a grunt or two. His range is so diverse he could do double duty and no one would notice. see more on Alan Tudyk