I was reading some of the negative comments about GameStop in the NWR 2006 thread (and also the story which sparked them), and whilst I can understand how one could be angered by such encounters, were they really so bad as to swear off the chain altogether?
First off, the employees will vary greatly by store location. Some stores do have employees who are actually knowledgeable about games and can help out the uninitiated without sarcasm or snide remarks. It's the ones who don't really know about games who can be a problem. One time I asked the clerk for a Nunchuk attachment for Wii, and she had no idea what I was talking about. I explained to her what it was, and she said "Oh, you mean a Nunchuk controller." Really? Couldn't make that connection? Anyways, if you don't have a GameStop near you with friendly employees, then I can understand never visiting them. However, unless you've actually visited each store in your area, I think it is a bit unfair to assume the entirety of the chain has terrible employees.
That said, some of their store policies are ridiculous. First off, I'm not really sure if they have any standards as to what condition they will accept a game in, as I've gotten a few disc games which were scratched to all dirty floors and couldn't be read at all. If these games were actually tested then they would have known they didn't work. Also, each used game has a set price regardless of condition, so games missing the box and/or manual aren't any cheaper.
Once I did a little experiment to test my suspicion that they put non-working game returns back on the shelf, by marking the game I had returned. Sure enough, when I went back a week later there it was sitting on the shelf. I guess they will continue to attempt to sell it until they sell it to somebody who wouldn't be bothered to return it.
The open-box display case thing for new games is pretty dusty table as well. I never buy new games from them any more because you never know if you'll get a sealed copy or not. The last "new" game I bought was Super Mario Sunshine, which was opened and already had a couple of scratches on the disc.
EB Games was better than GameStop. Even after the buyout, they still had better prices and store setup. That's where I bought many of my Nintendo 64 games from because their used games were all out on the shelves instead of locked behind a glass case, and were generally in good condition. I don't remember ever buying a non-working game from EB.
These days I only go to GameStop when I'm looking for GameCube games, as they're used prices on Wii games are barely less than new. Their GameCube prices are hit or miss, though they definitely have some better deals than whats on eBay. What really bothers me though is that they've started putting the price sticker underneath the plastic cover and on the paper insert itself, which is going to at least wrinkle up the paper when attempting to remove it. That's just plain illogical to put stickers there, it's like when they'd put stickers on cartridge game labels even though there's plenty of non-label space available.
When I started writing this topic I had the intention to be more positive, but I guess that didn't work out...