Some thoughts on the movie (I'll probably be adding more thoughts
and reactions and modifying this post as time goes by):

http://journals.aol.com/noelbotevera/MyJournal/entries/1057

Excerpt:

Cars is pretty much okay, about par for Lasseter (I'd be hard put to
name a favorite--not because I love his works (I don't) but because
I don't have many fond memories of them). Pixar, with Lasseter
behind it, seems to revel in trying to animate unpromising material,
from toys (which are fairly anthropomorphic) to bugs, to fish, to
automobiles, no less. Do they succeed? Eh--the cars at certain
angles have a startling photorealism--but who wants photorealism
when you can just watch NASCAR on TV? The stylized bits are more
interesting, somewhat, but there's only so much human expression you
can squeeze out of a front bumper and a pair of headlights--the
movie really stands or falls on its voice performances, and other
than Larry the Cable Guy (who's mildly amusing as a tow truck) and
one other exception, the cast is pretty much undistinguished.