I felt exactly the same way when I first got my D200; then all over again when I got my D3x. I'm fully expecting to have the same feelings when my D800e finally gets here ! (Hopefully after all the reported early production and software bugs have been worked out, though.)
BTW, I still have both of those older cameras - the D200 is now dedicated to IR photography, and I will never get rid of the D3x, it's still too capable of a camera regardless of what else comes down the pike in the forseeable future.
Oh, I can certainly identify with your love of medium format, as I used a Pentax 6x7 for many years before becoming fully digital. Ironically, I finally sold it to help pay for the D800e !