I have been playing the Witcher lately, I am up to chapter 2 at the moment. Its a good CRPG similar in style to NWN or the Baldurs, but you only ever control the one character and you wont be rolling in magic items and have a thousand spells to choose from like most D&D games.
I think that if you're a fan of western (ie D&D style) computer role playing games you'll enjoy the Witcher.