There are test images out there at Imaging Resources taken under controlled conditions that seem to indicate the D7000 excuse my expression kills the D300 as ISOs increase. My camera arrives this week so I can't say from personal experience yet but based on IQ alone I expect my D7000 to easily replace my D300.
There still seem a few die-hards out there (I was just reading a thread at Naturescapes) unwilling to accept this and claiming D300 retains more detail at high ISO. Nevertheless based on your excellent description of where the D80 was limiting you, I think yes it is a no-brainer D7000 for you! You will of course have to make the decision
Either way moving from the D80 having 35 or 51 points is going to be an improvement. Realistically it's going to take me at least a month to evaluate AF in the field. Since I plan to also get the D400 it is no risk for me to "make do" with the D7000 AF.
I think the better question for you is D7000 or D400.