What is best Nikon lens for studio/portrait photography?

I want to know what the best nikon lens is for portrait photography. The top couple lenses would work as well.

The dual cameron black guy one from one tree hill the photographer character uses i've personally found to be very reliable

I have a Nikon D40 and it does some pretty amazing portraits and action shots. It's an 18-55 mm lens. Hope that helped!

Do you have a full frame or APS sized sensor?

Prime lenses give the best image quality
Zooms are easy to use and convenient

If you choose a zoom choose a good quality one with f2.8 to give you the option of throwing the background out of focus

Primes for an APS sensor a 50mm and 85mm f 1.4 or 1.8 depending on how much money you have

full frame 85mm and 135 or 150 mm f1.4 or 1.8 same as above

I shoot portraits with a wide range of lenses depending on what effects I want

Nikon's 85mm f1.4 which is also known as the cream machine for it's bokeh.

85 mm Prime Lens with the lowest F-stop you can afford. The lens's sweet spot is 2 stops over the widest setting. But if space or budget is limited a standard zoom lens will give you amazing results. Remember it's not the lens so much as the mood and lighting you artisticaly create. Just try to get space between the subject and the background, and experiment with soft light. You can use standard inexpensive photo floods if you want… Try to get a "catch" light in the subjects eye…
Hope this helps…