Before I buy any more primes from Nikon, I'm holding off for AF-S. I may be waiting for some time.
I couldn't hold my breath any longer and I do a lot of low light photography (candid) so I jumped on the 85mm f/1.8, 50mm f/1.4, and Sigma 30mm f/1.4.
I sold the 85mm as it was just too long for indoor shooting and really didn't blow me away. I've owned several 50mm f/1.8 and 50mm f/1.4 and even played with an industrial/medical 55mm f/.85 I think it was.
Anywho, the f/1.8 vs the f/1.4 debate goes like this.
The f/1.4 has a hint more contrast (every bit helps IMHO), is decent wide open, beats the f/1.8 @ f/1.8. Extreme sharpness starts in at f/2.0 and is at it's peak at f/4.0.
Both lenses can resolve far more then our cameras can handle @ f/4 and beyond. So if you're using f/4 and up, then just get the 50mm f/1.8 and don't worry about it. If you shoot a lot of low light and/or like to get sharp at 2.0 as well as have better contrast...then you *need* the 50mm f/1.4
Edit: I doubt it matters, but some photographers are nutty. The 50mm f/1.4 weighs considerably more then the 50mm f/1.8. It is really a completely different design, and not just the "same thing" but a little more light.
If you are
and have the money roll to back it up, you want to get the Nikkor Noct which is a 58mm f/1.2 with hand ground aspherical elements and a god of both bokeh and night time shooting....since it was designed for astronomy photography.