As far as Pixar movies go, Ratatouille wasn't exactly the best the company has ever delivered. While the vast majority of movie goers have enjoyed the film's story of a scent-gifted rat who takes on Parisian cuisine, I can only say that I found the movie humorous, but by no means an instant classic. Though any Pixar film is better than any other studio's animated feature, I found Ratatouille fell behind The Incredibles, Finding Nemo, the Toy Story series and even A Bug's Life, and if it generates a sequel, I don't think it'll find any legs.
As a kid, I remember a children's book on a mouse named Anatole who worked in a french cheese factory with a career as a cheese taster. It could be that with that background, and having already seen a 9-minute sneak preview of Ratatouille via a promotion from Pixar on our TiVo, I felt that the story was an old one by the time I saw it. I was amused by the characters, and enjoyed the story, but much of it didn't work for me, from the age-old geek gets girl subplot, to the family crisis caused when the main character sets out on his own. I also wasn't keen on the imaginary friend chef, or the ultra-difficult food critic, who echoed the evil queen stereotypes in Snow White or Sleeping Beauty. The show also seemed quite dark, especially if being marketed toward young children.
Would I recommend seeing the film? Sure! But only once, and don't expect it to be the best movie you've ever seen. For other, likely more positive, comments, check out Webomatica's take on the film.