Flirting with Disaster is a great movie. I will also say that Robin Williams, to my way of thinking, is a huge step above most of the others. He has done some very silly stuff, but rarely is he simply two dimensional and obnoxious as Jack Black and Jim Carrey can be.
Steve Martin also has had some great roles against type-seeing him in The Spanish Prisoner, while not a great movies, was a huge change, plus the drummer in my high school band wrote and directed Novocaine, which starred Steve Martin and I thought he did a great job of interpreting the madness that is Dave Atkins.
Everybody's mileage varies here!
Edwin