Originally Posted by fatBastard() 
Oh and the paths in The Witcher is mostly about choosing a side in a conflict. The is no good or evil, merely shades of grey. Don't get me wrong I love the Witcher and have nothing bad to say about the game, but I think it is a bit unfair using the Witcher "choice model" as a comparison when talking about Good vs Evil choices.
That's precisely it. The evil in The Witcher is understandable, realistic, motivated, and logical — including but not limited to things you have to take a stand on. The fact that things are rarely unambiguously good or evil only makes it more interesting: evil is often very much about your point of view.
I for one can't fathom what's so difficult about doing evil right in computer games, since there are plenty of examples in literature and movies to draw from.