VGC is my first and probably my only one. I've visited others like gamespot and they were either filled with rage-filled trolls or they just seemed fugly. VGC seems to have the most educated members and it has a nice design.
I'm also on Playstation blog. I submit an idea every now and again. I've joined a few developer websites (Guerrilla Games, Zipper, Naughty Dog, etc), but I'm pretty inactive.
What about you?