Gnome 3 (at least under Ubuntu 11.10) seems to have been shipped with a number of features missing. For example:
Root is not needed.
- No easy way to change the screensaver (follow this: http://www.makeuseof.com/tag/change-screensaver-ubuntu-1110/).
- No out-of-the-box way to change the system fonts (you have to use gnome-tweak-tool)
- No out-of-the-box way to change the theme settings (follow this: http://www.omgubuntu.co.uk/2011/10/how-to-install-gnome-shell-themes-in-ubuntu-11-10/)
For me, the most annoying one is the lack of a user-friendly way to set any second/external monitor as your primary one (i.e. where the Gnome bar/task bar will appear).
You can set the orientation of the monitors in the settings, and how you want them aligned but that's about it. Here is a screenshot of the Display settings dialogue:
Long story short, open a terminal and enter the following:
$xrandr --output VGA-0 --primary
If you don't know how your external port is called (VGA-0 in my case), you can press Tab after the "--output" to see the list of interfaces X recognises. Simply replace VGA-0 with what you see fit.