Last night's problem seems to have vanished; I can't really see taking the MBP to the Apple Store and telling them it wouldn't boot last night, but everything's ok now. What would they look for, gremlins?

Anyway, it's cool that everything seems to be normal. One thing that kept the panic in the background though: I have time machine backups through the time I left the house on Tuesday, so the only things I would have lost would have been the emails - the two screencasts aren't on my home backup, but they are on the server in Cincinnati. Knowing you have backups certainly helps ease the alarm.