I feed whatever I can get! Variety is key, and other than that it is whatever your dog handles well. There are no really great cuts and there are not bad cuts except for weight bearing bones of large animals, those can break teeth and most people avoid them.
I feed whats on sale at the supermarket, what I can get locally raised from my farmer friends, what people accidentally hit with their truck, hunter leftovers and occasionally what is available at a local co-op. As long as it is mostly meat and a little organ and a little bone with plenty of variety you are good to go. If you are also feeding kibble you don't have to worry as much about the organ and bone.