OSX Mountain Lion - Login hangs after restart Mac Book Pro purchased in November, 2012, running OSX 10.8.current (Mountain Lion).

I shut down all apps, and restarted the laptop.

After the reboot, I selected my account and provided my password. The laptop hung with the apple logo and the spinning gear for about two minutes.

I restarted again and logged in as Guest. No problems.

I restarted and tried my account again. The laptop has now been stuck on the spinning gear (not the beach ball) for 10 minutes.

My home directory is encrypted, but I don't get any messages saying the laptop can't access the filesystem. 

(And, of course, I'd muted the speaker before I restarted, so I don't get the start up tone. I'm going to give this attempt a few more minutes before trying to boot into safe mode.)

This is a totally new type of problem for me. Does anyone have any hints on what to look at to see what might not be starting properly?

Thanks!

UPDATE 1

I couldn't manage to restart in Safe Mode (shift key). I did restart into Restore mode (Cmd-R) and was able to run Disk Utility. The disk itself passed all verify tests, the Encrypted LVM was inaccessible.

While in Restore mode, I picked Start-up Disk... from the Apple menu and provided the password for the encrypted LVM. That was accepted and the partition appeared.

After restarting, a test login is again hanging...
Whatever is was, CMD-R on restart and reinstalling the OS fixed it. :-/