Might as well finish this off:
6) Men In Black - As long as we all agree that the second film did not happen
7) Mars Attacks - Yeah, it has its weaknesses, but earns a place just for the scene where the Martians are playing the "We come in peace" recording as they blast everything to heck
8) Hitchhiker's Guide to the Galaxy - I love the "So Long and Thanks for All the Fish" song
9) The Man With Two Brains - Because any list of comedy films without Steve Martin is just wrong
10) Tremors - Because the worms rule.
(Honorable mention, Bill and Ted's Excellent Adverture, Cherry 2000 [don't care what Rotten Tomatoes ranks it], Demolition Man [Stallone on a list of comedies is usually problematic], Critters 1 & 2 but not 3, A Boy and His Dog [just for that awesome final line of dialouge, Lilo and Stitch)