It depends on the dog. I recommend a dry holistic grain free kibble mixed with either a bit of water or low sodium chicken broth every now and then. Kibble pieces can get stuck in their teeth when they chew it (if they chew it, my dog doesn't) so you would need to get him used to you brushing his teeth a couple times a week with an enzymatic toothpaste (which you should be doing anyway, regardless of diet). Cans of wet holistic brand food should supplement his dry food as neither should really make up the entire diet.
Try foods like Holistic Blend, Chicken soup for the soul, Innova Wellness, Orijen, and there are others that people here feed.