I think I've thankfully been quite lucky regarding video game purchases, I'm really having to think which ones I'd say were regrettable...I think probably Morrowind on the Xbox, this was after having played Oblivion on Xbox 360, so the loading times really put me off, I hardly really started it. The music is great though. Perhaps I might have another go at it, though I still haven't played Skyrim yet, that'll take priority.
Remember getting Vagrant Story on the Playstation, though for some reason I ended up returning it without having played it...not sure how this happened now, because it's always looked like a pretty good game to me.