Ehh, I have to agree with the too much hype thing. I bought the first one. Excellent co-op, but it really wasnt anything that great to me. Id had better multplayer in Unreal Tournament and such, and the campaign by yourself is pretty boring and not really fun (I thought).
Personally, Im in awe of a few other games now, most specifically Kingdom Under Fire. Such a beautiful, beautiful game. Most fun Ive had in a long time with a game.
That said, I will eventually get Halo 2, but not right now. I have a few other games which I really want to get my hands on first. I simply must buy Ninja Gaiden. I beat it on a rental, but I really want to play through it again...and that never happens to me.