This game is gonna rock! Looks slower and more strategic than Halo 3, but the graphics are top notch. Definately the next big shooter, the last one being GRAW.
Multiplayer is definately the biggest selling point, and my favorite thing about GoW. UserBase and all that, big as Halo 2? Probably.
Too bad Tony Hawk Project 8 is releasing the same day. Bad timing by Activision's part.