I got a chance to use a 50mm G lens this past Saturday night, actually - great lens, great quality, focuses silently - but not worth the $500. If you really need silent focusing, OK, but for most uses, it doesn't make a difference since the noisy focusing really isn't that noisy IMO.
Now, I'll admit that I prefer manual focusing with my primes - I often find myself fighting the AF because I can't be arsed to change the focus point. And this is where I really prefer my AF-D version - on MF, the focusing is unbelievably loose. It responds to the slightest touch and I can focus from near to far very quickly. Unfortunately, Nikon built in a dampener (perhaps necessary because of the SWM) into the G version that basically puts in a maximum speed with which you can turn the focusing dial, and it continues to turn even after you've focused to the maximum or minimum distance that the lens focuses too (whereas the mechanical AF-D focus dial stops when you hit infinity or minimum focus). When focusing by feel, this slows you down when you try to pre-set minimum focus distance because you have to look at the barrel and see where the focus is. I absolutely hate it.
So, at least for my shooting style, I would recommend you stick with your D version. It's half as expensive as the G version and IMO it handles much better. See if you have a friend with the G version or if a store near you has a floor copy so you can see for yourself.