Favorite beer? Man. That's a tough one.
My favorite TYPE of beer is an IPA. A very strong, bitter, hoppy IPA. For the winter months, though, I like to turn to Porters and Stouts, and generally heavy beers.
My favorite brewery for a very long time was Dogfish Head. I absolutely love their beer, and have never had one I didn't like, but they stopped shipping to Tennessee. The Dogfish 60 minute IPA was my standby, and the 90 minute IPA is still one of the best beers I've ever had.
My new favorite brewery is Stone Brewing. Their Stone IPA is one of the better typical strength IPAs. Their Ruination IPA is a great stronger IPA, akin to the 90 minute IPA. The Sublimely Self Righteous Ale is another great one from them.