Switching to Full Frame ?

I also have a D7000 and have been trying both the D600 and D800.

While there is indeed a difference, it is not night and day, by any means.

I think putting a mediocre lens on an FF body will not gain much, putting a better lens on your D7000 will be better - and cheaper.

Also, the D600 is even less of an upgrade - granted it has the FF sensor but in terms of features it is not any better than your current camera.

I would consider buying some Lenses that you can use later I even if your end up upgrading. This way you don't really lose much (or any, if you buy used) value.

The 50 1.8 is a cheap and great lens that would work in both DX and FX.

While the 24-70 2.8 is obviously a great choice, it is quite expensive, has no VR and is very heavy.

A used Sigma 17-50 2.8 (if you get a good copy) would work great on DX and the crop mode on the D800 (or even D600 at 10.5 Mpx).