I saw WALL-E a few years back on Netflix Instant. I don't really know why I didn't see it when it originally came out, but it's one of Pixar's best films so far.
The tone of the movie is rather different (at first) for a Pixar movie. The cute robot WALL-E is the only robot cleaning an life-less Earth in the distant future after humans left when they polluted the planet too far.
And I loved his relationship with the robot EVA. I did think it was rather silly that the people who left for space are now obese and can't even stand up.
I think WALL-E is the only Pixar film to truly rival the original Toy Story as their best animated feature. Don't miss it.