If you get a good deal and are prepared to spend a bit more, you might be able to get an 85mm f/1.8 AF - a true portrait lens.
The G lens has had very mixed responses - and OP is shooting on a DX body anyway. The G has a 58mm thread, the D a 52mm - besides, that doesn't mean that it is 'better' glass at all. A high quality fast prime with a small filter size could easily destroy a larger zoom lens with a larger filter size. Nicer coatings? Both the D and G are multicoated, and the G hardly incorporates any of Nikon's recent lens technologies - no Nano coating, no ED elements, no aspherical elements. The G does have an autofocus motor, but the D90 can autofocus the D lens just fine because it has it's own autofocus motor built in to the body. There is manual focusing on the G lens; wrong information is at best misleading, at worst becomes picked up and ends up becoming the norm - please don't spread it :shake: