Definitely the ones from Aliens. I mean c'mon, "Independently targeting particle beam phalanx. Vwap! Fry half a city with this puppy. We got tactical smart missiles, phase-plasma pulse rifles, RPGs, we got sonic electronic ball breakers! We got nukes, we got knives, sharp sticks...", says a lot about them. The fact that they're a "squad of ultimate badasses" doesn't hurt either.
PS: It's USCM (United States Colonial Marines), not USMC (United States Marine Corps).