Your real investment is in lenses. The advantages of going with an entry level is lower price, ease of use and often size and weight.

I shoot a Nikon D5000 and it has the full range of manual features, plus a menu system that is geared more toward those making the transition from P&S to a DSLR. The only thing it lacks that the prosumer models has is weather sealing and metal body, and ability to use older legacy lenses.

I will eventually add a prosumer body to my kit, but for now my D5000 does all (and more) than I need. My reccommendation FWIW is start with a D5100 kit, add a good tripod, flash and begin to build your lens kit. By the time the D5100 body begins to limit what you can do they ought to be out with the D9000 Prosumer body and by then you'll know enough to know what you really need/want.

The D7000 is a GREAT camera. But for the price of the body alone you can get a decent D5100 kit that will take pics every bit as good as the D7000.

Just my opinion FWIW.