“Linux Mint 12 comes with a brand new desktop, built with Gnome
3 and MGSE.
“MGSE” (Mint Gnome Shell Extensions) is a desktop layer on top
of Gnome 3 that makes it possible for you to use Gnome 3 in a
traditional way. You can disable all components within MGSE to get
a pure Gnome 3 experience, or you can enable all of them to get a
Gnome 3 desktop that is similar to what you’ve been using before.
Of course you can also pick and only enable the components you like
to design your own desktop.