this is a fantastic camera. many ppl i think will be trying to decide whether they should purchase this or the canon eos 400d. i think i should start of by saying that an on paper comparison is not going to help anyone decide which they should get, and i would suspect that those looking for an on-paper comparison are those that are only going to unlock the full potentials of either of these fantastic cameras only very slowly, rather than those that will be looking for a specific set of features.
to cut a long story short, out of the box, either will give u fantastic sharp pictures that will leave you wondering why you didnt upgrade from point and shoot cameras ages ago. however, the canon's white balance left a little something to be desired compared to the d80. in the automatic modes, i prefer the nikon's picture, but theres not much in it terms of sharpness, but maybe some elements of personal taste in terms of the overall look of the captured images would send some buyers in one direction or the other, compare reviews online to get a better idea.
i would say tho that in favour of the nikon is the metering system, the viewfinder (bigger and brighter), the status display (which is combined on the lcd in the canon), the 2 control wheels (vs one on the canon so u have to go into a menu if after setting aperture u want to set shutter speed) and a better kit lens, better build quality, and better ergonomics. in favour of the canon are the sensor cleaning and price and bundled software (RAW converter).
both cameras will give u tack sharp results, but i would suggest looking beyond that to make ur decisions; the nikon's feature set is geared to users who want to do more than point and shoot and are already familiar with using aperture priority and shutter priority etc. from that point of view, i believe the nikon will give more satisfactory results, and give u the oppurtunity to do more with ur picture taking; its almost on a par with the d200 (though of course its not weather sealed).
in summary, the d80 is great, and i thoroughly recommend it!