Bad and Good Karma

Upgraded Ubuntu to the latest (9.10, Karmic Koala) on my work machine yesterday and my home machine today. Encountered a bunch of problems:

1. Ubuntu Firefox Modifications and Tab Mix Plus still don't get along. The solution is to disable Ubuntu Firefox Modifications in the Add-Ons window in Firefox. I caused myself a lot more trouble trying to debug that one than fixing it actually required. It's a bizarre bug, but only an issue if you use Tab Mix Plus, and really easy to fix once you know what's going on.
2. autofs is still not handled quite right in the boot process. Only an issue if you're mounting your home directory from the network using autofs, but with all the good work they did on the boot process, you think the devs would have caught that one.
3. Speaking of network-mounted home drives, if you have a lot of them, gdm breaks because it tries to mount them all for no good reason.
4. Obsoleted packages were not cleaned up on my work machine at the end of the upgrade process, due to some minor error in some debathena package.
5. The menus in emacs don't update properly. Workaround is to set GDK_NATIVE_WINDOWS=1.
6. Random crashes in gnome-terminal. Possibly this bug? That's really, seriously bad. Actually, it's random crashes in zsh (a non-default shell). Tried downgrading.
7. Had to reinstall some stuff to get Japanese language input working again.
8. Bad behavior on the part of the SmartLink modem driver can cause sound to stop working. If you don't use your modem, the solution is to go to System > Administration > Hardware Drivers and disabling "software modem".
9. Got a bunch of error messages during the upgrade talking about dbus_move_error()... that doesn't seem to have been a real problem, though.
10. Mass operations (backups, anyone?) on Window-format hard drives have been badly broken.
11. The upgrade breaks mp3 support. To fix, remove .xine from your home directory and install (or reinstall) libxine1.
12. The upgrade randomly moves the hue setting in Totem (Movie Player) all the way to the left (this affects a setting also used by other applications, evidently). To fix, go to Edit > Preferences > Display and click "Reset to Defaults".
13. Compiz (desktop effects) breaks workspace switcher drag and drop. Solution is to go to System > Preferences > Visual Effects and set that to "None", but that results in a less pretty desktop, obviously.
14. A new installed-by-default font breaks fonts.conf. The solution is to remove the misbehaving package with "sudo aptitude remove ttf-wqy-zenhei".

There seem to be some really significant good changes, too, though: The easy programs installation / removal utility has been changed from Add/Remove Programs to the slickly designed Ubuntu Software Center. A lot of audio stuff has been improved (although that comes with new issues, as well). Pidgin has been replaced by Empathy as the default IM client (Empathy can do video conferencing, but I don't like the interface quite as much). The boot time is quite a bit faster. Fresh installs also get a new boot loader and an improved default filesystem (ext4 instead of ext3).

Also, a lot of the problems above don't hit most users. Still, unless you need to be on the cutting edge, I might suggest delaying the upgrade for a month or two.

Edited: Reworking this post in place instead of adding new posts on the same topic.