Looking for a new Camera lens for D90?

I need something for portrait photography, one lens I have been looking at as the 17-55 2.8 Nikkor. The low F-stop on it will be great for controlling DOF. Any suggestions would be great, thanks!

Added (1). I have also been looking at the old school Nikon Nikkor 85mm f/1.4D AF Telephoto Lens. Because of its Bokeh

You need the new AF-S 35mm F/1.8 lens that goes for around $200. Trust me this is the best purchase you will ever make.

The portrait lens used by most photographers is the AF-S 50 mm f/1.4

Yes, with the 17-55 mm f/2.8 lens at the 55 mm focal length wide open can control depth of field, however the reason the 50 mm is preferred for shooting portraits is because the sharpest aperture is two stops down. That means with the 17-55 mm f/2.8, you would have to stop down to f/5.6 which would perhaps give you more depth of field than you want. Two stops down using the 50 mm f/1.4 would be at f/2.8. The sharpest aperture and good control of the depth of field as well.

Have you had any conversations with local professional portrait photographers?

A great portrait lens is the Nikkor 105mm 2.8. Adds nice compression to the image, although you have to stand further back