I got my world clock to work by choosing "Denver" as my location, instead of "Boulder." I suspect it just knows about airports, since there's a list of sub-places for Denver, and they all look like airports. Still, that doesn't completely explain it, since Boulder has an airport, too -- it's just smaller.
Checking Place Windows, to select that compiz-fusion plugin (System->Preferences->Advanced Desktop Effect Settings) fixes the "windows open under the panel" problem.
After a huge amount of unsuccessful hacking, I finally made my desktop box at work completely unuseable. adamk, in #compiz-fusion, on Freenode (IRC), showed me what to remove and install to get the right drivers. "Then reboot and cross your fingers." When it came back up, it all just worked.
Well, except for printing, but that never works. :-) Maybe today.