I've fed Diamond foods and found them acceptable and they are reasonably priced. They are usually found at feed stores. Their website is at
http://www.diamondpet.com/. Some advice about matching a food to your dog and switching foods is also found there.
WalMart carries some good food as well in the MaxxNutrition brands.
Generally speaking a hard-running pointing dog in season needs a food with protein close to 30% and fat content 20% or more. The lower the moisture content the better. Price doesn't always equal quality when it comes to dog food.
I don't feed my dogs the same food year-round. I lower the fat content and feed the same amount in off season. My dogs seem to eat about the same quantity no matter the fat content and get heavy in the off-season if I don't lower their calories.