As it seems metacity is running (as you can change workspace), can you first try to run unity-2d-panel and unity-2d-shell from a command line (ctrl + alt + t to start one) and see what you get?
As it seems metacity is running (as you can change workspace), can you first try to run unity-2d-panel and unity-2d-shell from a command line (ctrl + alt + t to start one) and see what you get?