AFnord: I don't want my games scattered all over the place, as I'll just forget what I have.
xyem: I'm solving that problem by writing up a list of games I have. The list is the "one place" all my games are.
I'm using Backloggery for that, just to be on the safe side, but the problem is still that I won't get continiously reminded of the fact that I own the game. I know what games I have on GOG, Steam, Gamer's Gate & Desura as when I download one game from there, I'll see the other ones. With games on other sites, I need to know that I want to play a particular game in order to find it (and I won't just start randomly browse my list on Backloggery, that sounds boring ;) )