I work at a quick order restaurant, which is similar to fast food in that the food is quick and you order it at the till, but it's not fast food because everything is from scratch and prepped at the restaurant.
As for true fast food, I'm a Wendy's guy. Baconators are amazing. I also really like Arby's. Arby's roast beef burgers are fantastic. I eat fast food in moderation though, not very often and I don't go crazy when I do. I like it once in a while, but I certainly don't live off it.