What lenses are much similar to the nikkor 85mm f/1.8 in quality?

I'm looking for a zoom lens but with a smaller focal length than an 85mm due to the 1.5x crop sensor on my d90

Added (1). The 85mm is very high quality in terms of portraiture

A 50mm f/1.4 works very well as a portrait lens on an APS-C sensor camera like the D90.

For a zoom… I really like the 24-70mm f/2.8 lens but it will cost more than your camera did!

You'll find hundreds of people bangin' this drum. The Nikon 50mm f/1.8. The 50 1.4 is awesome. The 50 1.8 is by most accounts just as sharp and does just as well rendering color. The difference is the 1.8 is about $100. With the crop it's a 75mm equivilant, a good length for portraits. Look up the Nikon 50mm 1.8 Flickr group and see what you can do with it.
I own a Nikon 28-70 2.8, Nikon 70-200 2.8, Tokina 11-16 2.8 and I still love this cheap little 50mm.

Both 50mm, 1.4 and 1.8 are very good.