In GoW I used to be able to take my friends (and most people online) 4v1 easily with the sniper rifle, but I played CoD4 for such a long time I'm nowhere near as good. But in my anticipation for GoW2 I'm sure that I will be playing GoW a LOT in october and early november. That is if my 360 arrives when I want it too, which is basically anytime before Fable2 comes out (October 21). I'm really looking forward to playing you guys :P
As for Halo 3, I've kind of lost interest, the only reason I was still entertained past a few months was because of rank and forge, After I got to major and got the new maps, I pretty much stopped playing. Kind of a let down from Halo 2. But I suppose if enough people were interested I would play.