This enhancement was previewed last January at SolidWorks World 2011 and I remember sitting there thinking, yes, finally!
As a user that deals a lot with customer data or creating models using our customers 2D drawing, units are always something that I seem to switch back and forth between a lot. In SolidWorks 2012, this will be a lot easier. In the bottom ride hand corner of the Status Bar, you will see a button (located next to the Help button) that shows what your current units are set to. Now, with a simple click in the Status Bar, you will be able to quickly change your units and/or have access to the status units screen in Tools > Options.
If the new Recent Documents enhancement was a homerun by the SolidWorks developers, this would be a 3 run homerun. The 1 thing that would make this a grand slam would be to add units as an option to be added to a keyboard shortcut (without a macro). Either way, this is a great enhancement that will be very,very useful!