Although you can easily create shortcuts via dragging those icons from the "Places", in main menu, but still they'll show the shortcut arrow (which is changeable of course) + since they are just standard shortcuts, you won't be able to access the original "properties", etc on Computer or the Home folder for instance either.
So if you want to know how to enable these icons on Gnome desktop (I'm using Ubuntu 10.10 for this tutorial), then this is how you do it!.
1. Open your Terminal and issue the below command,
Note - Don't use the "sudo" attribute, because if you do so, the settings will be applied to the Root user, not to your current user account.
2. This should bring the Gnome configuration editor (a Gnome desktop setting manager, which are kept separately per users), see the below screen-shot.
|The Gnome configuration editor main window...|
3. Now from the window, go to (from the left side), "apps" -> "nautilus" -> "desktop".
4. After clicking on the "desktop" menu, you should be greeted with the below window.
5. As you can see, four settings with check boxes are unchecked by default. So all you have to do is check the appropriate box to enable that icon on your desktop!.
For instance, if you only want the "computer" and the "trash", icons to be visible, then simple check the boxes in front of those settings (OK, it sounded like a bit of disrespect to your intuvision, but I had to be precise :) ).
After making the changes close the window and you should see those icons back on your Gnome desktop!. Any questions ??....