I thought Pitch Black was ok. Boondock Saints rocked. I thought it was a great movie, definitely underrated. Pearl Harbor, I have no interest in watching that piece of crap. Event Horizon was pretty good too. Kindergarten Cop was eh...not worthy of being on this list IMO.
I voted for Mallrats because it really is underrated. I like it 2nd of the all the Kevin Smith movies behind Clerks. Chasing Amy would have been great, but I hated the ending. Dogma was eh...Haven't seen Jay and Silent Bob yet...
Other ones that I would add to the list are Zero Effect. Actually that's the only one that comes to mind right now. Ben Stiller is good, and Bill Pullman does a brilliant job in this. Best acting I've ever seen out of him, which isn't saying much, but still.