I live in Arizona so there's a fast food mexican food place that serves authentic mexican food and that place is one I go to the most and it's called Filiburtos. It's also open 24/7 so it's like mexican food heaven whenever you get that craving in the early mornings =P. Other places I enjoy are...
McDonalds as main burger joint
Jack in the (Box) Crack: When I don't feel like driving to McDonalds or it's midnight and I wanna get a burger. The McDonalds that's near me ain't open 24 hours /sigh.
Little Ceasers Pizza: Now this place rules, 5 dollar pizzas? Man pepperoni is the only topping for me at 5 dollars. Only downside is it's not open 24 hours. Curse you Little Ceaser guy!!!
I love 24 hour food places since I really don't eat meals like breakfast lunch or dinner, mainly because of my work that has me on all times of the day/night and the other being that I'm a gamer and I'm mostly grinding experience or pwnin noobs (I used to play WoW, Aion is my game now.)