cogadh: With games like that, the game is still tied to Steam as its DRM. You cannot play the game without Steam and you can be locked out of it at any time by something as simple as a failure of your network (let's not even get into the fact that Valve can arbitrarily decide to lock you out of your games at any time, as has happened to a few people here). Why in the world would you want to do that to games that you already are completely free to use as you want? If you really want your GOG games in Steam that badly, just create a shortcut to the game within the Steam client. That way you are able to use Steam to organize and manage your games, while not tacking any of the nasty Steam DRM on to it.
No, I'm not talking about Steamworks games.
For example, when I bought Amnesia, I bought it through the developers website. This got me two things: a DRM-free copy of the game I can download anytime and a code I can enter into Steam. This means I can have the game on my steam account, with all the benefits that brings (for those of us who like steam), but it also means I can download the game from the developers site DRM-free, if for some reason I can't access my steam account. I did the same thing with Spacechem, Prey and a bunch of other games.
A similar system on gog would allow people who want to use steam to do so, at absolutely zero expense to anyone who doesn't want to use steam. That way, everyone wins.