Overrated movies I guess would be movies that are ridiculously popular or excellently reviewed but aren't worth the hype. My list:
Babel- Various annoying people do incredibly stupid things and get screwed. Nice going, idjits.
Bowling for Columbine- Depends on your political leanings, but objectively speaking, it sucked. 
The Insider- YAWN.
Pirates of the Carribean 1,2,3- I like Depp, but each one is worse than the one before.
New King Kong- Boooring.
Ocean's 11,12,13- Make it stop! Your banter is NOT witty!
Shrek series- Mike Meyers is only marginally funny at his best. And that was called Austin Powers.
Gosford Park- Exactly who is the target audience here, if not people like me? Boooring.
A History of Violence- Dumb, unimaginative, slow, pointless. So many descriptors from which to choose.