The following are the steps I've used to install Ubuntu 12.04. Since I do not prefer Unity desktop, I remove it and install Gnome 3. Here are all the steps, and even some Gnome 3 extensions that make the overall desktop very user friendly.
First thing, after I get the default installation done, is install the Gnome 3 ppa, and get Gnome 3 installed. I go ahead and throw in my favorite dock (Cairo-dock), my favorite system monitor (Conky) and browser (Chromium):
sudo add-apt-repository ppa:gnome3-team/gnome3
sudo apt-get update
sudo apt-get install gnome-shell gnome-tweak-tool gnome-session-fallback cairo-dock conky-all chromium-browser
Once that is all done, time to permanently remove Unity:
sudo apt-get purge unity unity-2d unity-2d-places unity-2d-panel unity-2d-spread unity-services unity-asset-pool unity-lens-* unity-scope-* liboverlay-scrollbar* appmenu-gtk appmenu-gtk3 appmenu-qt firefox-globalmenu thunderbird-globalmenu unity-2d-common unity-common libunity-misc4 libunity-core-5*
With all that completed, it is time to go ahead and give the desktop a reboot. You will then be presented with the option to select Gnome as the desktop environment. Select that, and login. Once in, I always install the following Gnome 3 extensions:
Advanced Settings in UserMenu
Alternative Status Menu
Frippery Move Clock
No Topleft Hot Corner
Removable Drive Menu
Usually, the last step I do is go into the Advanced Settings (found within the user menu from the upper right power button), and select the Shell option. I change the "Arrangment of buttons on the titlebar" to "All".
With all of that done, the desktop is a nice, familiar environment, ready to launch Chromium and install all of it's extensions.