As is the trend of videogames these days, solid voice casts for some games come from Hollywood.
Halo 2 is no exception. In fact, it boasts quite a few notables in its voice actor line up.
Robert Davi-- who usually plays bad guys in many films, and the occasional good guy. You may remember him from Die Hard as Special Agent Johnson (no relation to Agent Johnson).
Keith David-- From movies like They Live, Pitch Black, Chronicles of Riddick, and Platoon. (not to be confused with David Keith.)
He voices the Arbiter, the Covenant character you occasionally play in Halo 2, when the scene focuses on Covenant Ops.
Robin Atkin Downes-- this name should be very familiar to sci-fi fans...especially those who enjoyed Babylon 5. He played the human ranger on the show...and he also starred in another videogame....one very near and dear to our hearts. He played young Ensign William Adama in Battlestar Galactica.
Miguel Ferrer-- Robocop, anyone?
Ron Perlman-- Well well, the Beast just seems to be getting into all sorts of stuff these days. From Alien Resurrection and Hellboy just to name a couple of flicks.
Michael Wincott--the gruff voiced heavy from films like Robin Hood: Prince of Thieves, The Crow, and Alien Resurrection (with Ron Perlman).
Orlando Jones-- You remember the original "Make Seven Up Yours" guy? Also from movies like Double Take, Bedazzled, to name a couple.
Laura Prepon-- OMG....wow! From "That 70's Show!" One of my alltime favorite redheads (next to Alyson Hannigan, Lindsay Lohan, Molly Ringwald, and Gillian Anderson). She voices a Marine in this game.
Michelle Rodriguez-- Latina hottie from SWAT, Fast and the Furious, and Resident Evil. (Also, apparently an avid videogame player.)
Well...those were the ones I could immediately identify.
Just some FYI.
Martok