Apple has released Thunderbolt Firmware Update v1.1, which addresses a problem with the mid-2012 MacBook Pro (when using certain Thunderbolt cables) that prevented some bus-powered Thunderbolt devices from working as expected. The update requires Mac OS X Lion 10.7.4 or later. (Free, 442 KB)
Full Screen Quick Look in Snow Leopard
When viewing files in the Finder in Snow Leopard, instead of pressing just the Space bar to enter Quick Look, press Option-Space to display the selected document in full-screen Quick Look, expanding the preview and hiding everything else that would otherwise remain visible.