My 2 pennies
It is cool that they decided to do a four player campaign, that will be the main reason I buy it. Though, I've played the Halo 3 beta and its just way too much like 2 for me to get excited about it. One of those games I'd rather play with friends only as there is way too many obsessed hardcore types playing this game that make it no fun to casually play online. I was really looking more forward to Unreal Tournament 3, which is now going to be a PS3 exclusive, through '07 anyway. So I guess I'll be getting a PS3 soon. The PS3 is slowly ramping up their titles, and gradually gaining in popularity among my crew. Though, the online PS3 play still leaves a tremendous amount to be desired. A huge plus for the 360, in my opinion, is Achievements. Everybody loves achievements.