Gamestop is more for the crowd who like to get Black Ops or a similiar game at launch and then proceed to sell their $40 dollar game they bought last month for $12. Those kind of people have to get the flavor of the week game and Gamestop appeals to them. However these people have wised up and have started using Craigslist to sell their old games.
Real collectors stay away from Gamestop like the plague. I have been disappointed in dealing with them except for a few rare times going back to Funcoland in like 98.
However people like Suicide Bob from "Tru Life, I am a Gamer" go into Gamestop to preorder games. I saw him at my local store talking about how Silent Hill Homecoming sucked
http://www.youtube.com/watch?v=uE9x8JPrwFc