I have been drinking Wild Goose's Snow Goose Ale almost exclusively for the past month. It's probably my most favorite "good beer" I've come across. Wild Goose is part of the
Frederick (MD) Brewing family.
Snow Goose is a well-balanced ale that's spicy (like most winter beers) and has hints of chocolate, caramel, and a little bit hoppy. I found a pretty good (albeit verbose) review
here.
Oh, I also tried the Sam Adams Winter Lager from the tap not too long ago, and it was really really really good. I wasn't too impressed with it in the bottle but man, it is great on tap.