First the good news. Even if you don't have children, you will enjoy Wall-E. If there is a brand-name for quality in movies, it is Pixar. The movie is visually brilliant, taking full advantage of animation's ability to show us vistas of an imaginary apocalyptic future and a giant luxury space liner.
The movie consciously borrows so much from other science fiction, notably 2001: A Space Odyssey. It is also a biting satire about man's consumerism and increasingly sedentary lifestyle. See if you can't recognize life at a resort in the Wisconsin Dells in 700 years in the lifestyle of the starship Axiom.
I do caution that I think younger children experiencing their first movie might find the subject a little heavy, incomprehensible, even boring. The action and the plot more than makes up for it for most kids, but I was glad my 3 1/2 year-old stayed home with Mom. I also wondered whether the movie has enough appeal to hold the attention of a typical teenager. On the other hand, my seven-year-old loved the movie, even more than Cars.
But otherwise I think the typical family willing to shell out the big bucks to see a movie at the theatre will have an enjoyable time.
One note about the plot. Yes, it's an environmentalist's nightmare, complete with freely bashing Wal-Mart (about as subtle as a note tied to a rock thrown through a window). However, for a post-apocalypic science fiction yarn, the story has a very optimistic component and a belief (ultimately) in the human spirit.
Now the bad news. Judging from the previews for the next Disney movie, Beverly Hills Chihuahua, it doesn't appear Disney has learned anything from Pixar.