Vet here.
My go-to recommendations are Purina ProPlan, Science Diet, and Royal Canin. (My pets all eat ProPlan.) They are pretty pricey, but not as pricey as Blue Buffalo and some of the other fancy/trendy foods that are actually inferior in terms of R&D, quality control, etc. Don't waste your money on "grain-free," because it has no health benefits in dogs... it's just spin-off of the whole grain-free fad in humans.
If you're looking for something cheaper than that, Iams and Purina One are good options.