My 2ยข is that the D7000 is a worthy upgrade. The low-light shooting abilities were game changing coming from the D80 (not too far from your D90). The video capabilities are also going to be better along with, well, just about everything else. Sure, nice expensive glass is great but really, are you going to shoot raw, spend hours post-processing extracting every last detail or are you going to chuck a lens on a body, shoot with pretty standard settings and use the in-camera jpg output? I'm in the latter camp. I'd love to have the time to tinker but I don't and I'm slowly getting over the fact that I can't do everything. Slowly. So I'm content with my everyday first gen 18-200 and occasional super-wide-angle 12-24 and get better pictures out of that setup because I actually use the setup.
Translation - door #1. The D90 is ancient in tech terms and the D7000 is a crazy good consumer DSLR body and you've got some nice glass from where I sit.