I have in the past used Tokina and Tamron lenses with good results, though not quite as good as the high end (and very expensive) Nikon glass I use now. The "other" brands are however very variable. Both Tokina and Tamron have higher quality lines called ATX and SP respectively that can be quite good while the cheaper consumer oriented lenses from the same makers are often much less so.
Even though you use the grey lenses, I'd suggest a web site called "Nikonians" as a source of information about alternative lenses. Many very knowledgable and helpful people over there, and they do have a couple of forums covering alternative brands. This forum especially may be of some help
http://www.nikonians.org/forums/dcboard ... &forum=157
You might also Google a store called KEH Camera (I think). They are a very reputable dealer of used photographic gear, and you might find a used grey lens in your price range. I have used them and been very satisfied...