Shaun of the Dead
Animal House
Burn After Reading (while not strictly a comedy, it has me in fucking hysterics all the way through)
Trains, Planes and Automobiles
The Hangover
Some of my favorites would be: Beverly Hills Cop
Ferris Buellers Day Off
The Birdcage
Fast Times At Ridgemont High
My Cousin Vinny
Ruthless People
National Lampoon's Christmas Vacation
It's Holy Grail or nothing for me LoB was just okay. I liked some of the sketches they did for Flying Circus but Life of Brian imo is an acquired taste. I've seen people's opinions of Monty Python soured because the first content they saw from them was Life of Brian.
Let me see...
Monthy Python (any of them)
Airplane
Liar Liar (who does not remember the Elevator pitch: "I've had better"... *slap*)
Bruce Almighty
Ace Ventura 1+2
Dumb & Dumber
Naked Guns (any, with Leslie Nielsen)
Spaceballs!
Wedding Crashers
Rush Hour(s)
Bill And Ted's Excellent Adventure
The 40 Year Old Virgin
Meet the parents/fockers/...
The Inspector General (Danny Kaye)