As a UW grad, I've got two suggestions. First, for mexican food, Pasquals Salsaria on Monroe St. is excellent. They've got great guacamole and it's a nice, informal place. It's also away from the typical rush of the campus area.

For a good burger, Dotty's Dumpling Dowry is the best in town. It closed for a few years (they were right near the capital) but have reopened right near campus. They're a block away from The Nitty Gritty, which is also a good place for pub food. Both are at the eastern edge of campus near the Kohl Center.