If you can afford the D7000 go for it is a lot better camera than the D90 actually is the D90 replacement
Having played with a D70, used D80s, D90s and now the D70000 along with D300, D300s, D700, etc I can tell you the D7000 does not feel like the replacement for the D90, it dang near replaces the D300s!
In my experience, when you go from say the D70 to D80, or D80 to D90, you get little bumps, for example:
Comparing D70 -> D80 -> D90 -> D7000
MP 6 -> 10 -> 12 -> 16
LCD 2.0 -> 2.0 -> 3.0 -> 3.0
AF Sensors 5 MC900 -> 11 MC1000 -> 11 MC1000 -> 39 MC4800DX
FPS 3 -> 3 -> 4.5 -> 6
Body plastic -> plastic -> plastic -> Magnesium
Meter segments 1005 -> 420 -> 420 -> 2016
Meter with manual lenses? no -> no -> no ->YES
Coverage 95 -> 95 -> 96 -> 100
Note the huge dispariagement of the new AF system, new alloy skeleton, massive metering system upgrade, ability to meter with manual lenses and viewfinder coverage increase. All things never before done. Also include dual cards, weather sealing and two user modes on the mode dial and I think you will see this seems like a whole new class of camera.
This looks like a new bottom of the line where the D300s currently sits, the D300s will be replaced by, lets call it the D400, and the D90 will remain right where it is. This moves the in-body motor cameras all to the midrange.
Of course then we have the name of the camera which falls in line with the lower end. Go figure
Allan