I voted for several things including: Spelljammer, Dragonlance, Greyhawk, Dark Sun and Planescape.
The 3rd edition Dragonlance stuff from Margaret Weis Productions (who have close ties with the Dragonlance community) is really brilliant, so I add my voice to the masses of people who want their staff to be involved in the 4th edition Dragonlance adaptation.
I would like to see WotC try to do something similar with the other campaign settings.
I also voted for Kara-Tur, Maztica, Al-Qadim and Other. So I'll explain those here.
The Other in my case is Forgotten Realms. WotC have already published Forgotten Realms Campaign Guide, but that really is not the Forgotten Realms I know and love.
I don't want to play in some sort of Forgotten Realms: The Next Generation. I say toss FRCG in the bin and give us a new revised FRCG that has no spellplague, no destruction of land, no NPC-killing time-jump, no destruction of deities and is recognisable as the same planet in the 3rd edition version. What I want is a conversion of 4th edition to Forgotten Realms - not a conversion of Toril to "Points of Light". This points of light thing is all very well for a bunch of new 4e campaign settings, but it isn't what Forgotten Realms is about. If every campaign setting gets this "Points of Light" treatement, I'm not going to buy any 4th editon books.
On top of a 4th edition conversion of the 3rd edition era version of Forgotten Realms, I want to see new versions of Al-Qadim, Kara-Tur and Maztica to bring the rest of Toril to life.
Sadly FRCG is so ugly, that it has made me loose my faith in Wizards of the Coast and I'm not going to buy any 4th edition products for at least 5 years. In five years time, they will either have started to make true conversions that I can enjoy playing, gone bust, or moved onto 4.5e and changed the way they upgrade things.