Human Clearlooks theme with the panels and menus consolidated.
Notice the notification area, volume control, temperature and time are set next to the workspace switcher and trash can.
The Applications, Places and System menus are consolidated into one parsimonious menu.
This layout gives you a little more screen real estate, which is especially useful on widescreen monitors, where most of the panel space is wasted. A 17″ standard screen gives you up to 1024 vertical pixels, while a 20″ widescreen will often give you only 900 vertical pixels.