said Sl�vek Banko:

| > Another, weirder issue: after the upgrade and a reboot, the machine
| > goes to GDM instead of TWM, which worked just fine before the upgrade.
|
| Yes, for some reason not yet known, it may happen that during the
| upgrade it may switch to another DM if another DM is installed.
|
| You can use dpkg-reconfigure tdm-trinity to switch back. Or uninstall
| another DM if not needed.

Thanks again. That's what I did; mostly wanted to kind of report it in case 
a.) it's a strange bug or b.) I had broken something else! (And as always, 
the TWM/TDM confusion is mine.)
-- 
dep

Some pictures:
http://www.ipernity.com/doc/depscribe/album