With Halo 2 hitting shelves on Tuesday, the magazines and websites are free to post their reviews, and they are doing so:
UPDATE: More review links from Voodoo Extreme:
Without providing an indepth review, at least yet, Voodoo Extreme's Andrew Burnes said "I loved it."
UPDATE: Slashdot now has a thread discussing the reviews of Halo 2 from major gaming sites. As usual for Slashdot, the majority of comments are negative.