Here are some facts that I've gleaned over the years from discussions with my pet food advertisers. It makes perfect sense to me.
Dogs are not carnivores; they are omnivores. They need all components in their diet; protein, vegetables and carbs.
Corn is the most important ingredient in dog food because it is their "energy carb." What you need to watch for on the label is if it is ground corn or corn meal. Ground corn doesn't state how rough or fine it is ground. It could be chunks, most of which would pass through. Corn meal is a powder and will give the best absorption value. The dog will get the most out of corn meal.
Rice is an inferior source of carbohydrates. It is generally given only when corn cannot be tolerated.
Protein is not one of those "the more the better" things for dogs. Too much protein over a lifetime is hard on the kidneys (for humans, too!) Cats have the highest protein requirement of all animals, and they only need 40%. Working dogs will do well on 24 or 26%. Puppy chow carries a slightly higher percentage because they are burning calories just growing. For added energy, add some fat, not more protein.
Stool consistency is largely influenced by fiber percentage. The higher the fiber, the bigger and looser the stool. I never buy a feed that has over 4% fiber. I prefer 3%.
All that being said, take a look at the ingredients label of this food. It's what I fed because it met all the above criteria:
http://blackgolddogfood.com/performance.htm
If it's available in your area I would highly recommend it, regardless of what it costs. If not, I would get as close to those numbers as I could.