Following the WoLpH's recommendation I am looking forward to enable Xinerama to set up 2 monitors to be 2 separate Gnome virtual desktops instead of one big.
But the thing I worry about is how to set it up correctly and not to harm Ubuntu's "Monitor Preferences" application, panel indicator applet or anything else.
If you have had any experience with Xinerama, would you be so kind to share?
I use Ubuntu 10.10 on my Toshiba L10 laptop with Intel 82852/855GM onboard card. And I switch (which, AFAIK, can be an inconvenience with Cinerama) monitor configurations (detach all monitors but a laptop's built-in panel, attach monitors with different resolutions) pretty often (sometimes many times a day).
As Ubuntu was unable to detect my graphics, I was to create Xorg.conf already, which has solved most of my graphics problems.
The last time I have had experience with writing Xorg.conf manually and setting up Xinerama was about 7 years ago, with Slackware and Matrox MGA G550 card. And I definitely wouldn't like to edit Xorg.conf every time I need to switch my monitors configuration.