I think it all just depends on who you ask. Protein in dog food ranges A LOT from somewhere around 23-24% to 45%. Some people swear by high protein some people say lower protein is ok. Even vets disagree on how much protein a dog should have. Somewhere in the 30-35% range is probably your best bet. You don't want it too high because then the kidneys have to work overtime but you also don't want it too low because dogs need the amino acids. It also depends on the dogs age, puppies and elderly dogs shouldn't have too much protein, but adult dogs should have more.
Yep, what Melissa said. I feed Fromms which is 24-25% protein and my dogs do fine on it. I personally wouldn't feed a high protein food unless I was actively working my dogs but everyone's opinion is different.
I feed Taste of the Wild and the protein depends on the meat and so they have a range from 24% to 32%. I have fed it all but usually end up with the 24-25% because I have younger dogs. Otherwise I would stick to a little higher protein level like 28-30%. Mine do get plenty of exercise.
I've been pondering this topic as well. I finally settled on Taste of the Wild. I bought the pacific and sierra mountain formulas. Brody is just shy of 11 weeks old so he needs less protein. When he gets older I will more than likely switch to the higher protein formula. It also depends on if your dog is a working dog and how much activity he's getting. Melissa and both Jane's have helped me a lot on this subject :) There are a lot of people on this site that can give you a wealth of information!