I too have used 10.04 since it came out and 8.04 for a couple of years before that. The "Unity" interface on 12.04 is different (I think it belongs on a smart phone, not a computer - but not to get on my soapbox)... Here in a couple of steps are how to make 12.04 look similar to prior versions.
1 Click on the top icon on the "menu" strip and search for terminal.
2 Open the terminal
3 Enter the following command
sudo apt-get install gnome-session-fallback synaptic -y
Enter your password when prompted. Once the installation process completes logout. At the login screen click on the little Ubuntu icon next to your name and select Gnome Classic. The interface will now be familiar. A couple of tips... To add a launcher or make other changes to the panel you must press the Alt key while right clicking on the panel. The above command installed the synaptic package manager in case you are more comfortable using it as opposed to the Ubuntu software store (or whatever it is called).