Friday night after a system update as my laptop was shutting down my FileVault got corrupted. I spent all weekend, aside from Friday night when Rhonda helped me not be so pissed about it and Sunday morning at church, trying to recover any portion of the data.
Word to the wise: if you're using FileVault you NEED to be making regular (read DAILY) backups. FileVault is very finicky, and it is very picky. And if you lose your FileVault disk image you are SCREWED and not even a Time Machine will help you. The only thing that makes this not so bad is that I had a three week old backup from when I got my new laptop. But it's amazing how much one does in only three weeks.