These commands work on Ubuntu Linux 9.04 Jaunty (with Adobe’s flash plugin) and Google Chrome (NOT chromium!) as of July 26, 2009 or so:
$ sudo mkdir /opt/google/chrome/plugins
$ cd /opt/google/chrome/plugins
$ sudo ln -s /usr/lib/adobe-flashplugin/libflashplayer.so libflashplayer.so
Then you have to manually start chrome with this command switch (or edit the menu properties).
$ google-chrome --enable-plugins &
Tada!
As a long time Linux user, I was disheartened to find getting a reasonable level of performance would be so much work. And would defy the old saw that Linux runs great in less memory than Windows.
This is a q&e summary of my experiences with Ubuntu 9.04 (Jaunty Jackalope) Desktop, and the various performance related issues that have dogged me to this day. Actually, some of these problems date back to 8.04, and were radically more pronounced on 8.10 which was almost unusable for me. Ubuntu Desktop 8.10 sucked OUT LOUD. At least from a Desktop performance perspective.
Update 2009-12-30: I have belatedly upgraded to 9.10, and my first, early impressions are that it is much improved. Probably due to improvements in the Intel video code.