Just a couple of days until release :3
I have played the first Witcher in the standard version which is said not to be as good as the unlimited edition. I still enjoyed it very much, though. The way you could shape the story of the game was intriguing: things you have done or said could make a difference at a totally different point of the story and could have influence things completely unrelated.'
Also, there was - unlike in Bioware's or Bethesda's games - never any way to make the 'golden' choice. Someone would always have to suffer, and someone would always think it's your fault.
Until now I do not know any games that could do this significantly better. Fahrenheit / Indigo Prophecy came close; the Mass Effect series and Dragon Age (2 more than 1 imo) had a similar feel, but I think The Witcher was the best of them (regarding interaction between choice, character and story).