If I'm going to be playing standard D&D, Eberron and Kalamar are the only settings that I'm really interested in. Although if my group wanted to play Greyhawk, or FR, or anything else, for that matter, I'd follow along without complaint. We're a good group that I have faith could make any setting fun.
And coincidentally, we were playing Eberron under one GM while I ran another game for the same group. Sadly, I think our Eberron game has ground to a permanent halt, but we'll see. We'd all be willing to pick it back up again.