I enjoy going to McDonald's and In & Out Burger.
I'm getting more and more fond of Moe's Southwestern Grill and just about any place where they make a burrito right in front of you. They're opening a Chipotle just down the street from me, and I need to check it out when it when it opens.
In & Out is the best burger I've ever had from a fast food joint. I was in Vegas a few years ago for a week and must have went there 5 times. I just wish they'd expand East.
White Castle is another of my favs...I always have to go there when I visit my family up in Detroit.
As for places I can actually go to in Houston...Whataburger is pretty good. Chic-Fil-A is good but expensive. And I usually hit up Wendy's on weekends...their value menu comes in handy late at night when you're drunk and hungry.