158.18's released the other day - i've got a 8600GTS in my HTPC and it's (so far) the card from hell. I'm running Vista Home Premium and it's causing sheer havoc with suspend/resume (hangs on suspend, black screen on resume).
From what I see on nVidia's own forums there's a lot of angry 8xxx series users out there - i'd really hoped that the driver situation had settled down after so many months of development..
TBH i'm seriously considering junking the card and trying the ATI option - all I want is for the machine to able to gracefully shutdown and resume (like all the other PC's I have!).