The D80 replacement is due any time between now and summer, yet I find it curious that there hasn't been a lot of speculation on what it might look like. Historically, a D80-replacement should be a handful of technology and state-of-the-art hand-downs from the reigning pro cameras and as much of the parts bin as is possible from existing consumer cameras, all wrapped in a polycarbonate body that isn't fully sealed. That means that you should expect a melding of D40/D60 and D200/D300 features. As in: D200 viewfinder, D300 color LCD, some creative subset of the D300 AF and metering (e.g., same AF sensor, but fewer AF options, coupled with the use of the 420-cell matrix meter for the Auto Area 3D mode), but with the reduced control set, the shutter, write mechanism, mode dial, and remote controls of the D40/D60/D80. Sensor? It could go either way (10mp or 12mp), but expect an auto cleaning function. Add Active D-Lighting and perhaps one of the Live View modes and you've got a new mid-range model that's competitive. The key question: will Nikon go further than that?
Some have noted some slight changes between the above and my original predictions and wonder about that. It appears that Nikon flopped their timing on a couple of models (D40x and D80 replacement timing), thus the timing is a little different than I originally predicted. As for the sensor, Nikon seems to have three options: the current 10mp sensor, the D300's 12mp sensor, or Sony's new 14mp sensor. Nikon hasn't exactly been pushing megapixels as much as the other makers, so I still insist it could go any way. Remember, given the number of bodies Nikon is making, there's a financial advantage to using the same sensor across bodies, thus my comment about it likely being the 10 or 12 megapixel sensor.