The Finder window toolbar in 10.1 used a traditional iMac icon to signify the computer. I customized my two machines (a cube and flat panel imac) each to have a respective icon. See my homepage to see what I mean.
However in 10.2, the toolbar already has a flat panel imac, but not the icon I wanted. I tried changing the icon as I did before in 10.1, however the toolbar icon would not change. It baffled me.
After some digging, I discovered that the imac.icns is in a new place: /System -> Library -> CoreServices -> SystemIcons.bundle -> Contents -> Resources -> iMac.icns ... you need to swap that icon to change the computer icon in the Finder window toolbar.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020824084008537