Damn, I love this movie....
I guess if it was the only music available on Earth, one might listen to these two selections from Hello, Dolly! (1969) over and over again. I happen to like them both, alot, but I wonder if I would if it weren't for the inclusion of them in WALL-E.
"Put On Your Sunday Clothes"
(I'll never hear this now and not think of WALL-E "humming" it.)
"It Only Takes a Moment"