My Gamestop must also be one of those rare "good" stores, because I was in it a couple days before the "official" release date for the demo picking up a strategy guide for an RPG I was playing. I just walked up to the counter, bought my guide, and took one of the demo discs with me without a single word out of the cashier.
Apparently, "good" GameStops aren't hard to find. Out of the three GameStops I attend to out of town none of them have given me any trouble. Sure they ask if I want to pre-order stuff, warranty etc. but they were always courteous to me and have yet to see any incompetence from the employees.
If you don't mind my blunt opinion, while I do agree that the whole chain is guilty of some dubious practices it seems that most horror stories are caused by the employees and not the store itself. And like I said before even the best companies hire the worst employees.
Once I went into a Gamestop and the person behind the counter asked if I wanted to preorder a game. Being courteous (it's part of the scout law, man) I replied, "No thanks, I would rather decide if I want a game after it comes out and get it then." The man told me that, "Dude that is the stupidest thing I've heard, how the hell are you going to get a copy of Halo 3 when it comes out." I responded, a bit more tersely, "I am sure that you will have plenty of copies, I think it would be dumb to not order enough of the biggest game coming out this year." His idea of a witty response was to imitate a crying baby, smashing his fists into the counter and screaming (really, yelling), "Whaaaahhh I am such a baby! I am too scared to pre order a game and I cry when I can't find it when it comes out!" As people turned their heads, he continued his show. I walked out, disgusted.
Then there are multiple instances of them selling me demo discs/cartridges in stead of the real game.
Yet another time, I purchased a brand new copy of the PC game Elder Scrolls: Oblivion. Not having seen one in stores for a while, I bought it. Turns out, when I went to buy some deodorant (or something) at the Target that shared a parking lot I found a copy of the game a full twenty dollars cheaper. Needless to say, I bought that version and went to return the more expensive copy I had bought at Gamestop. The person working there refused my return, saying they had the right to do so. I don't look like a criminal, at least I hope not, and there was no way in hell that I had copied the game within fifteen minutes and managed to do so without even breaking the seal on the game. So I was stuck with that copy and had to drive to two cities away to return it, because the guy had called his friend at the closer gamestop to warn him of the "thief".
So that is two gamestops marked off my list of available shopping locations. The very last bastion of hope is the one at which they attempted to refuse me the Monster Hunter disc. I will have to forgive them out of necessity.