What's a better choice? Nikon lens 50mm f/1.4G or Nikon 85mm f/1.4G and why?

I'm going to use it on general purposes and some modeling photo shoots

The one that is the focal length you need.
If you are on a full frame you may like the 85. If you are on a crop body you will probably want the 50. You may even want something wider on a crop sensor and the 50 on a full frame. It really depends on your style.
Do you currently have a lens that covers these focal lengths?
Set your current lens at 85mm and don't touch the zoom. Shoot with it. How does it feel and work for you at 85mm?
Do the same at 50mm. One will feel right for you

If you have a full frame camera body, go with the 85mm lens. If you have a cropped sensor camera body, go with the 50mm lens.

Nikon 85mm 1.4G is the cream of the crop lens… Or at least one of the sharpest lens out there for both Nikon and Canon, if not the sharpest for Nikon. The bokeh is nothing like it compared to other lens. It almost makes the subject like its a 3D image due to the bokeh effect. Its a perfect portrait lens on an FX body (full frame) and quite a telephoto portrait on DX since its equivalent to 127.5mm on FX. Professional photographers have these on their lens collection, its just that good, if not the best.

Nikon 50mm 1.4G is a standard lens for general purpose but very good low light and fast focus but the bokeh is not as phenomenal as the 85mm.

50mm f/1.4G is $484 Amazon.com 8/3/2011
85mm f/1.4G is $2299 Amazon.com 8/3/2011