Halo 3

So, the main reason why Halo 3 rules? Their choice in voice actors, including:

Burnie Burns (Church in Red vs Blue)
Gus Sorola (Simmons in Red vs Blue)
Matt Hallum (Sarge in Red vs Blue)
Jason Saldaña (Tucker in Red vs Blue)
Nathan Fillion (Malcolm Reynolds in Firefly)
Adam Baldwin (Jayne Cobb in Firefly)
Alan Tudyk (Wash in Firefly)
Katee Sackhoff (Starbuck in Battlestar Galactica)
John DiMaggio (Bender in Futurama)
Terence Stamp (General Zod in Superman II)

As an added bonus, Fillion plays the Sargeant.

( The Best Script Ever! )