GTX 670...i rolled back to 340.52, and have not had the desire to go beyond that as it is working well on the Win7 machine. Have a GTX 580 on a Win8 machine and running driver 331.65 without issue...if it ain't broke...
I recently upgraded my my vid card to GTX 570 and at the same time grabbed the latest driver (funny for some reason the older driver did not recognize the card swap from previous GTX 550 Ti). I have successfully used 344.11 with NBTP 3 and done rendering with the GPU option set on.
I am also using 344.11 without any problems. And yes I can use the GPU for editing and rendering without getting crashes - which was not the case with a lot of earlier drivers.
I've been using a GTX 570 since February 2012 on Windows 8 Pro 64 bit. It was frustrating for a long time when I bought the 570 and found the GPU acceleration wasn't usable with the then driver/Vegas combination. But drivers issued for quite a few past months now have all been fine. It may have been the upgrade from Vegas 12 to 13 that cracked it - I can't remember.
When you all install you're drivers do you choose express or custom? I'm just wondering if we should install everything Nvidia gives us or just the graphics driver?