Since over a month, I have a
Debian Etch DVD lying around. Last night, I finally finished backing up any valuable data and started the upgrade, closely following the careful upgrade instructions given in the release notes. This worked quite well, some minor glitches have happened, though. For instance, wmsensors and wmwifi were removed, although at last wmsensors is included in etch; I haven't checked wmwifi yet. Then my mouse stopped working. Turned out, I never updated gpm.conf from my old serial mouseman configuration to the newer usb mouse I have since quite some time. This was easy to fix, though. Finally, the installation of iceweasel aka Firefox 2.0 resulted in the loss of two of my favourite extensions: SurfKeys, which for instance allows to move between tabs with "o" and "u" and Reveal, which shows mini views of the contents of other tabs. I can live without Reveal but I'm going to look for a replacement for SurfKeys (yes, I use hit-a-hint and keyconfig, but I don't know how I can configure moving between tabs). There is probably more that needs fixing, but nothing spectacular so far.
Update: The surfkeys problem can be solved
(see this discussion).