Unity in Ubuntu 12.04 has come far away from its humble beginnings when it shipped with 11.04 'Natty Narwhal'. Gnome Shell has also improved significantly but some people still find them not catering to their needs that were satiated with Gnome 2 and yet at the same time don't want to change their base from the Gnome DE.
Cheer up people because in Ubuntu 12.04 you can get the Gnome 2 look, feel and functionality back yet at the same time be on the latest Gnome DE offering. I present to you Gnome Classic.
All you have to do is install 'gnome-panel' from the Ubuntu Software Center, logout and in the session chooser you will see 2 additions 'Gnome Classic' and 'Gnome Classic (no effects)'.
Select which ever pleases you and get nostalgic.
You can easily customise Gnome Classic to your liking by pressing Alt and right clicking on the panel which will present you with the option of adding a new panel, panel preference and adding applets to your panel. Enjoy!