[VinnyP]

In terms of image quality the outgoing D40x (now replaced by the D60) has the same sensor as the D80 and even the D200. What you gain as you move up the range are better metering options, easier handling, improved focusing, speed and build quality.
As has been said the lack of a focusing motor means your choice of lenses is limited not just in respect of the older short Nikon Primes but also at the other end of the scale with cheaper third party zooms but many are hoping this will change.
Nikon seem to have nailed themselves to losing focusing motors at least on their consumer models. This has already benefited all Nikon users as the independents have retro fitted a lot of their lenses with focusing motors. Sigma have even released a 50mm 1.4 USM to go with their excellent 30mm 1.4.
The older full frame short Nikon Primes although still optically very good have been around for a long time. A lot of people hope that the release of the FX D3 means that Nikon will review the non AFS lenses.
But as things stand the focusing motor and improved metering and handling of the D80 mean it has the edge over the D40 D60 BUT with the market flooded with 2nd hand D200s they may rate consideration. There is no guarantee that the D80 replacement will have a focusing motor.