I briefly ran a 4E campaign set in Ed Greenwood's Castlemourn setting, originally written for 3.5/OGL. Right now I'm running a setting that I've described as "Neil Gaiman and Guy Ritchie kill Eberron and take its stuff."
I don't know if I'd use much of a published setting, they're so sparse that I'd have to do just as much work to put it in my homebrew. I'm considering doing a Greyhawk game for the next campaign (around 590 CY or so), but that's because my current group is unfamiliar with it but interested.
A disgraced half-fey battlesmith artificer, whose alchemical knowledge came in handy when she chanced upon...
A clockwork assassin, who killed his employer and is now looking for the other constructs his creator made for decadent nobles, with the help of...
A winter elf warlock, whose tough childhood on the streets of the city tangled her up in the seedy underworld, currently served by...
A troll-blooded storm sorcerer, who makes "deliveries" in the black market while seeking his lost mentor.
I could never publish it, because it's so derivative. But hey.