How to install Gnome 3 without breaking Unity?

Solution 1:

There is currently no easy way to do this, GNOME 3 requires a major transition to the GTK+ stack (from 2 to 3) that has not been done in Ubuntu yet.

This is a goal for 11.10, but currently I'm afraid trying GNOME3 on Ubuntu is more of a one-way upgrade.

Solution 2:

I used the instructions at the attached link to install Gnome Shell on 11.04 without breaking Unity.

"By compiling Gnome Shell using the instructions in this post, all the packages the Gnome >Shell script will download and compile will not replace any existing libraries and it >will install in your home folder, so you don't have to worry about breaking stuff on your >system (excluding here the build dependencies of course, which are usual packages from >the Ubuntu repositories and will install just like any other package)"

http://www.webupd8.org/2010/10/install-gnome-shell-from-git-in-ubuntu.html