Forgotten Realms: I neither love or hate the realms. I like the NPC's, the high-powered magic (Magic of Faerun is one of the best books WotC has put out since 3E was released, along with the Manual of the Planes and the Psionics Handbook), the whole flair of the setting- but I would never run it, for the same reason that I wouldn't run Kalimar, Scarred Lands, Greyhawk, or any other published world- I prefer to co-create my own world along with my PC's. I'm trying to establish a long running world of my own design, and playing anywhere else just wouldn't work.
So far, the best stuff to pillage has been from the Realms (MoF) and Scarred Lands (Relics and Rituals). Kalimar hasn't given me anything very tempting yet, nor has Ravenloft, Iron Kingdoms, or any of the other settings.
My vote for best setting goes to Realms- keep the good, crunchy stuff coming!