Originally Posted by Prime Junta 
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.
Aahh … re-reading the entire thread I seem to have caught the ball and charged off blindly in the wrong direction with it
What you're saying is of course absolutely true. Though not even close to a Good vs. Evil choice model, it is a much more "realistic" and believable set of choices you're presented with in The Witcher. Heck, I sat staring the at the screen for a long time before I finally decided which faction I was going to support and that is a great example of an actual CHOICE rather than picking the correct color corresponding to the alignment you chose in the character generation screen.
Sorry about misunderstanding what you were saying when you mentioned the Witcher.