Natty Narwhal changed my layout

It really annoys me whenever i upgrade to latest version the look and feel of my OS changes completely.....now with this newest release I find my system is COMPLETELY different.... can anyone tell me how to roll back to the previous release or will I have to reinstall? Or alternatively, how can I get rid of the floating menu bar on the left of my screen and go back to the tried, trusted and perfectly acceptable menu bar with drop down menus......

thanks in advance for any advice :)