imho....the D80 is old school technology. However still a decent camera. My D90 replaces the D80.....and a lot of functions/features have changed as well. But I agree, the prices of a D80 is a lot better nowadays and you probably don't need the features of a D90. Whatever you do...don't go below a D70 as some lenses are non-compatible and will not auto-focus with the lower end models (D40, D40x, D60). Word of advice....spend less on a decent body and spend top dollar on lenses.
Also, you do realize that going the Nikon route gets very expensive compared to Canon. After I did my research on camera gear, I noticed everything Canon-related was a few hundred dollars cheaper. I just wasn't feeling the functionality and ergonomics of the Canon. It felt cheap. Either way the end results are always based on how much fun you will have when playing with a new camera.
Side note*....if you go Nikon....I have a kit lens for dirt cheap....as I have not used it
Nikon/Nikkor AF-S 18-55mm 1:3.5-5.6G DX VR
...and maybe my Manfrotto tripod....as I need a heavier/sturdier one