There's no doubt Canon glass is cheaper- but with longer lenses you'll look like a dork as the black, white, red, black look is just not aesthetically pleasing.
So, Nikon glass is dearer and is really based on the reassuringly expensive model rather than any real science but at least you look good.
Just suck it up and keep the faith
I see little point in upgrading to the D7000 from the D90- certainly for the things you are shooting. An upgrade to full frame or the fabled D400 would be a more sensible idea- even then, having a specific requirement that necessitates it is useful rather than upgraditits which is what you seem to have.
Anyone can buy the latest and greatest body but if there was no need it changes nothing but your bank balance.