Man that Game is beautiful, I'm really interested in it but more for the adventure horror aspects as opposed to the shooter aspects. I don't know if you could really compare it to Halo. Halo is an FPS through and though, GOW is an Adventure Horror Crossed with a 3rd Person Shooter. Two completely different games really.
I totally Agree with Chaos Theory being at the top of my list of best games.
Definitely a game that could pass as next gen. Just recently I managed to find a new and unsold copy of the Limited Metal Box edition... I jumped on that faster than a hobo on a ham sandwich. Now that I've finally finished the home theater in my basement I need to play though it again on the projector with the surround sound cranked up, my last time through all my good equipment was in storage so I was playing on a 32" CRT.
Speaking of games that could pass for next gen, have you played Burnout Revenge yet? That game is beautiful, maybe not full fledged next gen, but it certainly looks better than a lot of current gen titles, I can't wait to see what that one looks like ported to the 360 in 720p with FSAA