"Fixing Wall-E" While not Awesome Music per se, the beginning is a classic moment.
The Axiom is also a fantastic score. The parts that play when WALL-E and the spaceship are flying past the lunar rover and flag on the Moon, and then through the rings of Saturn, are almost impossibly beautiful.
It's surprisingly dark and scary for a Pixar film, but Swim Down is amazing. Starts off dark and hopeless but erupts into triumph at the end. It helps that this and 'Fronds like These' follows it on the soundtrack too.
The four-minute-plus "Married Life" underscores a dialogue-free montage that follows Ellie and Carl from the altar to Carl's arrival home after Ellie's memorial service — whimsical, lyrical, and heartbreaking.
"Carl Goes Up". "So long, boys! I'll send you a postcard from Paradise Falls!"
"Paradise Found", in which the clouds part to reveal Paradise Falls and the rest of the plateau in all their glory.