Since I brought up the whole cast thing... IF they were making a film based off the first game and they used Male Shep the following would be what I'd like to see. I adapt easily to casting choices though... So...
Commander John Shepard... and I don't want to seem like everyone else that has said this just because he's played Batman... But I feel Christian Bale would be the best choice..
Joker: Seth Green... Has to be Seth Green. Even if nothing else is even close to my cast IF they make a film based on the game it HAS to be him.
Garrus: Edward Norton with voice mods
Saren: Christoph Waltz with voice mods
Liara: Olivia Wilde... With SFX makeup, obviously.
Wrex: Ron Perlman with voice mods.
Kaiden: Eric Bana
Ashley: Erica Cera
Tali: Emmanuelle Chriqui with voice mods
Dr. Chakwas: Hellen Mirren.
Captain Anderson: Keith David (Duh) OR Morgan Freeman.
Ambassador Udina: John Noble
Mass Effect 2 characters:
Zaeed Massani: Gerard Butler
Jack: Natalie Portman
Mordin Solus: Neal Patrick Harris
Grunt: Vin Diesel
Miranda Lawson: If they don't get Yvonne Strahovski then Emily Blunt
Thane Krios: Javier Barden
Samara: Michelle Pfeiffer in SFX Makeup
Jacob Taylor: Tyrese Gibson or Michael Jai White
The Illusive Man: If no Martin Sheen then Bruce Greenwood.
I'd also be completely fine if the characters from the game (Wrex, Tali, Garrus, Grunt and Mordin) were voiced by the same people that voiced them in game. Although, I know that would probably never happen. I'd also love if the aliens weren't CGI (more so Tali) and just really good costumes with the voice actors I mentioned.