There's been some talk that EB can sell used/opened games as new. Apparently, employees can 'try out' a game first. I've never had a problem with that, but I rarely go there, if at all.
Last time I went there was to preorder NWN2 and get the prerelease toolset. I ended getting a digital version of the game anyway, so I cancelled the preorder. I did buy a DS Lite while I was there for that, though, but stores make very little profit from selling hardware.
Before then, I think the last time might have been for Wizardry VIII. As much as some people don't like EB, if it weren't for them striking an exclusive deal with now-defunct SirTech Canada, I wouldn't have gotten to play that, what with lack of publisher interest.