Which camera lenses should I use for portrait photography?

I have a Nikon D5000 with 18-55mm f/3.5-5.6G ED II Kit Lens and I really want to buy a new lens for portrait photography. Considering I'm a beginner, what would you recommend?

Added (1). Well by a beginner, i mean 2 years

Added (2). Well by a beginner, i mean 2 years

Get a 50 1.8 AF-S.

If you're just starting out, the 18-55 is a good starter lens. Learn before dumping a bunch of money.

35mm or 50mm prime that opens to at least F1.8. Or faster.

The 50mm f1.8 is a good place to start at 120$ but if you have a bit more money, you might want to splurge on a 50mm f1.4 instead (around 300$).
I personally love my 24-70mm f2.8 (1600$).

By two years, you mean you already know why the 18-55mm lens is not enough for you as a portrait lens? If you know why then see if you can find the right lens for you here.

http://keerok-photography.blogspot.com/2011/05/lenses-so-many-of-them-there-is-no-best.html