I'm back to shooting with a D70. I traded my D40 and Sigma 30mm f/1.4 for a D70 with a Nikon 85mm f/1.8. My first DSLR back from 2004 was a D70. I eventually upgraded to a D80, then sold it for a D40. Now I'm back to the old standby. I think I'm going to like it. I do miss the really nice screen on the D40, and the SD capability, but I like most everything else about the 70.
Here are the advantages of each piece of equipment: (as relevant to me)
-Much better screen
-Takes SD cards instead of Compact Flash
-Has AF Focusing screw to allow autofocus with non-AF-S prime lenses (The deciding factor)
-Has a dedicated bracketing button (see the next post for examples)
-Has two command dials
-More dedicated buttons
-More autofocus points
-slightly faster (larger maximum aperture)
-AF-S (so it autofocuses on the D40)
-Better focal length for portraits (The deciding factor)
Who knows how long this will last me. Unless I find a really good deal on a D90 (or whatever Nikon calls it when it's announced) I'll probably stick with the D70 for a while.