I would nominate TRU, BestBuy, and Gamestop. The reason for these three is I would probably have to flip a coin to decide my pick. I have to say I always look to Amazon first. They may not be creative and copy others sales but they always seem to have stock and my free prime membership and no sales tax makes for great deals...
I also am adding Gamefly. Not sure if I ever gotten a game in working condition from them. Even PS3 games that blurays are not supposed to scratch. They seem to have a nack for being able to make them unplayable before selling. Everyone else seems to have good luck but not me.