I agree with jaomul on this: the much newer sensor technology in the newer Nikon cameras has brought a really MAJOR boost in the ability to manipulate the files in post processing; this is the really,really major improvement with newer d-slr cameras. It's a very significant issue, and one I noticed on the very first day I upgraded from an old-technology sensor to a new, Sony Exmor-design sensor. Additionally, moving from 10 megapixels to 24 megapixels is a MAJOR leap in terms of how much you can crop an image and still have a high-quality final image.
In terms of body features, the D80 is still the slightly larger,heavier camera, and has the dual control wheels. Now, the 5500 has touch-to-focus, and has been made just a tiny bit smaller than its predecessor; I watched the Fro Knows Photo evaluation of the 5500, and he was very impressed with the touch-to-focus capability on the 5500, and found that it was useful for high-angle shots,etc..
Compared at snapsort....I see the Dynamic Range of the 5500 to be 14 EV, but the D80 a mere 11.2 EV; this is a major difference. Color depth on the D5500 is 2 EV better, and the Low Light High ISO score is a little bit under three times higher for the newer camera; these three performance metrics form the basis of jaomul's statement above, where he wrote: "
Image quality, or post process ability takes a massive surge upwards with the newer camera".
The shutter lag time on the D5500 is 201 milliseconds, on the D80 it is 250 milliseconds, so the 5500 is slightly quicker in reaction time, and it also shoots faster, at 5 frames per second rather than 3 frames per second. The 5500 has a much larger screen, 3.2 vs 2.5 inch, and the bigger LCD has 1.03-million dots versus as opposed to only 237,000 on the older camera. The 5500 is the only Nikon dslr I know of that has the touch screen feature.
Compare the Nikon D5500 vs the Nikon D80
D5500 has a 39-point AF system, D80 has 11. D5500 is CMOS, D80 is one of the last CCD cameras.
Compare the Nikon D5500 vs the Nikon D80
Comparing the D5500 in the snapsort category "
compared to other recent entry-level d-slrs" released within the last 24 months category, the 5500 is ranked #2 with a snapsort score of 92, right below the Nikon D7200 with a 100 score, Pentax K-3 Mk II third place at 78 points, see the others here
The best recent entry-level DSLRs
The D80 still has the larger, and I think a little bit better viewfinder, but the D5500 has Live View, swivel screen, touch screen, touch-to-focus, is smaller, lighter, fires off its shots faster and with less delay, and is the second-best entry-level d-slr released in the last two years, right behind dPreview's runner-up #2 Camera of The Year, the Nikon D7200.
I say it's a major upgrade, moving you forward, literally from
a 2006 camera to a 2016 camera.