Many games shops in Australia have an unconditional 7 day return policy, so I don't really get dicked if I buy a game and it turns out shit as I'll just take it back and swap it for something else. That said, because of the excessive price of Australian games and the general lack of interest I rarely bother with this, I'll often just pirate a game, dismiss it as crap and move on. Every now and then, if a game is reasonably priced and has no DRM (well, sometimes steam...but very, very rarely) I'll buy it, though a lot of the time this just ends with me having a game I never play (like demigod).
Ultimately, I'm quite happy to pirate games until something holds my interest. Before call of duty degenerated into shit I got a copy of a friend, and while it was a legitimate copy it probably counts as pirating, I loved the game and ended up buying 1, 2 and 4..I regret buying 4 and probably won't buy any again, but that's an example. Another example is killing floor, I played the mod and saw that the steam release was very different, so I downloaded an illegal copy, played it at a lan and all of my lan friends ended up buying it (myself included).
Oh, and you can be damn sure that any game I end up buying that has DRM, it will be cracked so I Can play it without having to fuck around with install limits, secuROM and whatever else they dream up.