In my years of gaming I've had some excellent DM's and GM's. Some I think are better when they're in charge of certain games. However, strictly speaking DM's, I'd have to say the best I've ever had was Wirty Penix.
Wirty's my dude and has been one of my core friends since I was in 8th grade. Unlike me, he came from a family of gamers. His parents both play D&D. We've spent many hours gaming (playing D&D and others). He's a creative guy and really knows how to make memorable npcs.
Several of the instances I've mentioned during the past thirty days have been Wirty related. He ran the evil game I mentioned, stopped a charging minotaur dead in its tracks using an immovable rod, created Gregor, placed the damn intact dragon skeleton in the dungeon, was DM during the craziest thing I've ever seen in game, and was the regular DM when I played Ulic. He also created one of the prominent halfling families in my games.