I don't think there's any doubt the D3 is a fine camera. The question -
- and you'll forgive me because I didn't see the original post -- is
whether you need that much camera.
If you're shooting for a living, and were doing so with your D70, you
may not need to drop $5,000 on a camera. If you have that much cash
burning a hole in your pocket, you might be better off going with a
D300, or something even more modest, and investing in some sweet
lenses.
Bodies become outdated pretty quickly. Lenses tend to retain their
value.
That said, if I had a spare $5,000, I might by a D3, but generally I
prefer smaller cameras.
Good luck.
.