The Wall-E score is magnificent, combining elements of electronic music that sounds artificial and vice versa to make a truly fitting soundtrack for an absolutely wonderful film. The music is played (or orchestrated, or composed, I don't know) in a light, lilting style, with a playful touch that's often amusing. I'll echo the other reviewers in saying "Horizon 12.2" is indeed musical perfection, and "M-O" is a brief stealthy interlude worth a mention. There's a swell of strings on "Fixing Wall-E" that comes >this< close to making me blub every time I hear it. If pieces like "72 Degrees and Sunny" and "Define Dancing" don't make you infectiously happy (and then others by way of you) you must be the most relentlessly, unflappably depressed person in existence and you have my sympathies. The variation continues with the frantic "Desperate Eve" and traditionally-tinged "Tilt", action-movie-score as they come.
The other, non-Newman tracks on the CD can't stand up to the score in my opinion, and although they're perfectly listenable, it would have been nice to have it totally isolated. Still, I can't recommend this enough. Heartwarming, painful, joyous, expressive and deserving to accompany the masterpiece that is the film.