This is more fast food, but Arby's rocks. It's got super-thin slices of hot roast beef (although probably pre-processed) in a hamburger bun. The Horsey Sauce is totally the key to this - without it, this would be a bland dry heap, so I apply the sauce very liberally.
I also like the potato cakes, although the curly fries are good too. It's a shame that these guys aren't as franchised globally as their McCompetitors.