I didn't get to vote either. Aw well...
A bit surprised by all the Greyhawk love. I run Greyhawk as well, I like how "setting neutral" it is - it doesn't have the huge regional differences of FR, yet you can still find a place where almost any campaign or scenario will fit right in. And those migration maps and the ongoing Flan - Oerdian- Suel - Baklunish conflict really get me going. Not that it has a lot of impact on play... but it does have some.
I like alot of what's been written for Golarion, but I miss the backstory that Greyhawk has - contemporary Golarion is cool, historical Golarion feels a bit lacking. That said, I've imported political developments from Golarion to my version of Greyhawk, so there is now an Andoran (former North Province), for example. And the really-far-back history of Golarion is also lovely, with Aztlan, Thassilonia, and the other lost empires.
For a third setting, I'd pick Al-Qadim because it is so very colorful.