MBP booting into setup assistant?!

I am typing this from my media center Mac Mini right now. About an hour ago I noticed there was a Quicktime update available for my MBP. I decided to install it and the system prompted me to restart. This would have been the first time my MBP has restarted since the middle of last month (I've just been sleeping it when not used). I noticed that there was nothing I could do to restart it. Pressing the power button and hitting shut down/restart did nothing as when i selected these options from the menu bar. So I decided to shut it down using a terminal command I found on these forums as opposed to force shutting it down. This seemed to do the trick.....

Then, when it restarted it went to the login screen as normal. Afterwards, instead of booting to the desktop it boots me to setup assistant just as I had done a fresh install. I freaked out and shut it down and immediately hooked it up to my Mac Mini via target disk mode to examine the harddrive. All my files and user account seem to be intact. I have no idea what to do here. The Mini (which is still on Tiger) cannot read my Time Machine backups so I am backing up crucial data to the Mini just to be safe.

What in the world is going on here?!