I like all kinds of beer. Ales (especially IPAs) and porters are my favorite, but I like a good lager or pilsner on occassion.
I think I'd have to say that Samual Adams is probably my favorite of all the beers I've had (I love their entire collection of beers). That and Yuengling; they have a good collection, too. I also like Sweetwater's collection of beers (they're a local brewery).
Beer! I like a good Belgian style ale, though I'm not a huge fan of the "burnt" style which seems to encompass a lot of Begians. I like just about any Ommegang brewery beer (Hennepin, in particular) and Orval ale. Hoegarten and Chimay are ok, but they have that burnt taste, so bleh.
Unfortunately, they cost an arm and a leg, so I also go for a nice lager (yuengling is my fave, but it's a local beer), pale ale, or IPA. Magic Hat makes some good stuff along those lines, as does Sierra Nevada.