1. Brütal Legend
The Bleeding Death (who in a shocking turn of events happens to not be a space marine, unlike the rest of dudes on the list)!
The Crimson Lance!
3. Halo 3: ODST
The ODST (game's whole cast)!
4. Section 8
The whoever you play in this thing!
5. Warhammer 40,000: Dawn of War II
The Space Marines!