TB,
I have a 50mm Nikkor f1.4D and I have it on my D3s quite often - my 'nifty fifty' is one of my favorites. From what I've read the 50mm f1.8G is a sharper lens, but again the f1.4D (older model of the one's mentioned) is quite an adequate little lens and can be had pretty cheap. Other than being newer I believe the only real difference between D and G lenses is the G series don't have aperture rings; e.g. aperture must be set in the camera. //IG//