I hate to admit this, because:
A) I wrote part of the Dawnforge book, and
B) I normally prefer more traditional fantasy settings...
But I have to say, I'm the opposite. I've had more story and character ideas spring to mind from reading Eberron than I have any campaign setting since... Since I can't even remember when, honestly.
If someone put a gun to my head and forced me to choose a favorite of the two, I'd probably have to say Eberron. Though that shouldn't be taken as any slight to Dawnforge; it's far and away one of the best published settings I own.