The Reuben at Arby's is pretty good. For me the bread is the most important part of most sandwiches, and the bread they use for their Reuben is delicious!
However, Arby's is a bit pricey for fast food. If I want a less-expensive option, I go for the Carolina Classic. I think they only have them in Wendy's restaurants in the Carolinas. It is a burger with ketchup, mustard, chili, and coleslaw. I like to get mine with cheese, as well. MMMMMMMM!