There's alot of debate about it, but it really boils down to what your dog thrives on.
I don't want to name a brand, because I don't want to give you a biased opinion - but nutrition wise, most commercial dog food brands are quite lacking. I recommend finding a premium dog food that does not have Corn or Corn Glutton meal in the first three ingredients. (Also, becareful with "grouping" which is a technique companies use to push Meat to the first ingredient. Look for specific ingredients like "chicken meal" instead of "poultry meal".)
If you opt against purchasing Ultra-Premium brands,You can take a trip to your local petstore, and see that some brands have premium dog food lines which have a much agreeable ingredients list. If not, check out some of these brands:
Eaglepack
Bluebuffalo
Canidae
Chicken Soup for the Dog Lovers Soul
Here's an additional link on RAW feeding as well, to have as an option. You may or may not like this idea.
http://www.rawlearning.com/rawfaq.html
Hopefully that helped, good luck!
