I have had consoles all my life, so as far as that goes I go with Gamestop. Personally, I have never seen how they rip everyone off compared to other retailers like Best Buy and even Wal Mart now.
I know I can just as easily sell my game for oodles of cash online rather than trade it in at Gamestop for a few bucks of credit, but selling it online requires waiting when trading it in at Gamestop is instant. If I had a collection of games, as well as the patience, I wouldn't mind selling online, but I dont so I dont.
I am in the market for a PC as of late, so I imagine I will be buying a number of things on Steam if a physical copy of the game is not possible. As much as I love the ease of digital downloads, physical copies makes me feel more secure.