I did a test shooting newspaper to see how much the extra pixels improve sharpness. Unfortunately I can't post pictures until I upgrade my membership. But I will tell you after zooming in on the D80 image at 1600% I could still read the print whereas I couldn't zoom in more than 400% on the D70 image before losing it's readability.
I am no expert at testing these things and my results may be flawed in some way so if someone else would like to make a similar test and post their results here I am sure it would be appreciated by many of us.
When the D200 was new there were similar posts comparing this with 6mpx cameras. I can't post my own comparisons yet because the D80 hasn't yet reached Australia, but I look forward to it! Geoffrey In the golden west - Western Australia
Western Australia (a state nearly 4 times the area of Texas)