A few of my favorites--in no particular order:

Deschutes Black Butte Porter
Westmalle Dubbel
Orval
Big Sky Brewing's Ivan the Terrible Stout
Tyranena's Rocky's Revenge
Guinness
Any of the Rochefort beers
Lindeman's Cuvee Rene Gueuze
DuPont Saison

I could go on, but I've got to get back to work.

David