I saw Cars over the weekend. As I expected, it was a lovely example of Pixar's strengths: attention to detail, research, multi-level humor, and subtle characterization. I can't wait to get the DVD to find out what lovely jokes I missed the first time around. The voice talent was good, particularly Luigi (voiced by the incomparable Tony Shalhoub). The animation was phenomenal, particularly the scene when Doc Hudson shows his stuff. I've also heard the soundtrack highly praised.
That being said, I think the plot was a little bit predictable. I think Owen Wilson was well cast as Lightning McQueen, but it was simultaneously a little too easy a characterization for him. No stretch.
The jokes were great, particularly Mater's "happier than a tornado in a trailer park" and "he did what in his cup?" If you see it, make sure you see the credits. There's a great joke by John Ratzenburger. Also, the list of people they thank for the research portion is fascinating. Those who know of John Lasseter's obsession for research will not be surprised.
Overall, my feelings on the movie are overwhelmingly positive. I'd say it's a 3 1/2 stars out of 5, and I'll definitely be getting the DVD.