if you are at PHX, you have to go to El Bravo in concourse D. It is really good Mexican food & just about the best food you'll find in any airport.
The tortillas are fresh, the food tastes homemade, the service is friendly and fast, and there is a good selection.
my personal favorite is the red chile burrito. A fresh tortilla filled it shredded beef cooked in chile colorado (red chile sauce) and nothing else. No filler like beans or rice. And it is less than $7.
In fact, I like El Bravo so much that I try to rouye through PHX just to have it.