If you money is not a big issue for you, then get on the list now for D80 and sell your D70s when you do get the D80, probably two months from now. There should still be a market for a used D70s, especially if the shutter actuation count is low. Have you had your D70s for more than 30 days? If not then Ritz should take it back. Also if not more than 30 days, maybe you can still get a Mack warranty. That's usually transferable and could increase the re-sale value of the D70s if you do decide to sell it in the future.
But honestly, D70s is a great camera. I have the D50 that I bought a few months ago, and when I saw the specs for D80, I know I made the right decision of buying the D50.