As soon as I updated my MacBook Pro Retina 15″ to the 2012 December 17 update http://www.macworld.com/article/2020833/apple-releases-wi-fi-efi-updates-for-2012-macs.html, my Ubuntu 12.04 VM running on VirtualBox 4.2.4 croaked.
Workaround was simple, just disable 3D acceleration on the Display Settings tab.
Figured someone else might hit the same snag!