OS X 10.6.3
Well, the laptop (2007 era Macbook Pro) updated to 10.6.3 just fine, but the iMac got itself into a bit of a block; it rebooted with a black screen, but it was running (Finder found the system, and I was able to ssh into the box). A reboot seems to have gotten its attention. Came up, and the only issue was a delay in my lunch's arrival :)
