IGNXbox overrated DOA3, Amped, Raw, and JSRF, but Halo was NOT overrated. Hell, IGN.com gave Halo their "game of the year" award.
GameSpot even gave Halo a 9.7 as Bond metioned in his post. Electronic Gaming Monthly (best console mag) gave Halo their "game of the year" award as well.
I'll admit...some games get overrated and some get underrated. Mario Kart 64 only got a 6.7 rating from GameSpot. Resident Evil only got a 8.9 from GameSpot, and I think the game deserves at least a 9.5 rating.
Ratings by these "game sites" shouldn't be anyones opinion.