We just got back from the first showing of Ratatouille at the Grand 18.
It's really excellently done. Monsters, Inc. is my Bar of Excellence for kids' movies. This was only a half-step down and far more engaging than Finding Nemo, which dragged at times.
Both boys were fairly well mesmerised the entire two hours*, which for the youngest is quite rare. They stayed that way through the credits, too.
see the trailer
nine minute trailer (sixth video down)
*it didn't feel like that long. Another good sign.