Just an aside, but I've found the packrat feeling has spilled over to Steam, I really like opening my games list and seeing it scroll on forever, and I have to admit, when there's a '5 or 6 games for £10' weekend deal on, I'll generally go for it even if I only want one, just for the hell of it, and knowing I've have a bunch of unknown titles to mess with later.
While I can see PC games dying in the high street, DD won't be the only choice, places like Amazon are still going to order hundreds of copies of new PC games, and they'll usually be half the price of GAME(stop) (UK/US).
Personally before I rush out and buy anything, I'll be doing some research, checking Play, Amazon, Game, and even places like Tesco, before I decide where I'm gonna be buying it, and if I'm not in a rush I'll leave it a couple of months and get it for closer to £15 somewhere.