As far as 24 hour cafe's go around here, I'm a fan of the Palms 24/7 Cafe. They have a pretty good Chinese food menu late night and the sandwiches are tasty too. I've never had to wait in a long line and the food always comes quick. One time, I ordered beef chow mein and it came out with no beef in it, but the server was quick to fix it and the manager came over to apologize. He gave us a discount and we were totally pleased.
The wait staff is attentive, even on busy nights and always treat you well. The wall of TVs is cool, especially to watch the game while you dine.
Love it!