I haven't had my DSLR for six months yet, but I'm already dealing with camera envy. The object of my affection isn't even a mid-level or professional camera, but a Nikon model which is aimed at a similar market as the D60: the D3000. Comparing the MSRPs according to Nikon Canada, I would have only paid forty more dollars for this camera.
It's not as if the D3000 is a much better camera than the D60 (in my opinion, anyhow). In any event, I believe that the most important part of any camera is the person taking the photos. Besides, my number one reason for upgrading was to start taking professional-looking photos; Nicky (my DSLR's nickname) undeniably does that very well. One point where the D3000 trumps my D60, however, is in the number of focus points; the former camera would have given me eight more to work with. Having said that, this is only a significant issue when I use spot metering (i.e. metering which uses one focus point as opposed to the whole viewfinder).
Still, I knew about the D60 having only three focus points before I purchased it. Having only had one focus point with Old Faithful, I was very appreciative about gaining two more. Trust me - on my next upgrade, I'll surely gain way more than two.