I did not preorder Halo 2 but I will be waiting at the doors when Circuit City opens at 10am tomorrow.
From all the reviews I've seen and read it seems to be a near perfect game, but maybe thats just a bunch of hyped up gamers. I guess we'll have to wait until its out for a week or two and then we can really see how good it is.
My favorite review is at:
Teamxbox.com Halo 2
They offer a lot of free movies and screenshots.