I think Shoot 'em Up would be fun to watch drunk. To most its either a love or hate thing so we could get some very opinionated reviews here.

Other good drunk movies:
Either of the Jackass movies
The Big Lebowski
Donnie Darko

and one of my all time favorite so-crappy-its-awesome movies: Killer Klowns from Outer Space (Yes I have the DVD with special features) http://www.imdb.com/title/tt0095444/

spiffy

P.S. I vote for Killer Klowns