The classic. Apparently part of the reason Planescape: Torment didn't sell well was that this dude's face was all over the box art.
I think it works perfectly for the character - he's lived lifetimes upon lifetimes and died death after death, so it make sense he'd be a leathery mass of scar tissue. And it immediately tells the player that this RPG is about to do stuff you haven't seen before.
And yeah, I think it's great that Geralt is uglier than your average protagonist. However, as some people mentioned, he's not The Nameless One ugly. He's conventionally attractive under the scars and mutations. Good character design, though.