If you are over here on the west coast then it has to be Del Taco. It is 10 times better than that shit at Taco Bell. Del Taco is very affordable, pretty healthy for fast food and is open in the early AM.
www.deltaco.com
I miss DelTaco...had one here in Houston when I was in high school back in 1984.
My Favorite Houston Fast Food...
James Coney Island: www.jamesconeyisland.com/
Princes Hamburgers : www.princeshamburgers.com