Gabriel Knight 3 is one of my favorite adventure games and although it, as Dom put it, has some faults it's still a very good game. The music is maybe the best in any game ever and the voice acting is imo in most cases of very good quality. I also wonder what the fuss with Tim Curry's voice acting is all about. I understand that someone might like Dean Erickson (the guy that played Gabriel in GK2) better, but imo Tim Curry does a good job in playing Gabe, and I also like the voice of Grace. It fits the character very well indeed.
The graphics was a bit of a disappointment actually and especially the backgrounds look pretty terrible, but the graphics in an adventure game isn't the most important thing after all, is it?
The
article that Scott Bilas has written about the making of Gabriel Knight 3 is a very good read for you that haven't read it already.