Halo 2, UT2004 (I believe), and others were actually built using a steady blend of Maya and Max. Its funny looking at jobs for various companies

Modeller of a company> "Must be proficient (sp?) in 3d studio max"
Animator of the same company (on the same project)> "Must be proficient in Maya and MELscript"

All I got to say, is Okino is living the high-life :p