None are!
I just get the hand-me-downs on permanent loan. The D100 is the first DSLR Nikon made, way out of date, but works. The D2x I just turned in. Nikon is very quiet about their camera releases, no real advance notice. The D2x came out and there was a rumor of the D200, but my dad gave up waiting on the D200 and bought the D2x, a few weeks later, the D200 came out.
Go figure. The D300 was his primary camera until a week ago, when he picked up the D800e. I'll have to give him the D300 two or three times a year when he goes on photography trips.