Can't login via GUI, but can login on console

Backstory: I restored a Time Machine backup of my laptop onto my new iMac and everything has been working great until today. A long time ago I connected my laptop to an Active Directory domain. Once I restored the image to my iMac, I changed the computer name in Network Preferences. This had not caused any problems.

Today I was going through the Account Preferences screen and noticed the Login Options had "Allow network users to login" checked, and it listed Active Directory as a user source. I thought "wow, that must allow AD users to login to my machine with their credentials, I sure don't want that!" so I unchecked it. Then I got spinning beachball of death and I couldn't click on anything. I decided to take a nap and hope that it would resolve itself, but an hour later it was still spinning.

I put the iMac to sleep with the Power button and then woke it back up. A dialog flashed on the screen that said "to access this computer you must login" or something like that. It had my account named filled out already, so I typed in my password, hit enter, and the status said "checking password." It stayed like that indefinitely, while nothing else responded (not even ctrl optesc or ctrl opteject or any of those key combos).

I turned the machine off and turned it back on again, but when I entered my password it waiting for about 5 seconds, then just displayed the login window again.

I typed '>console' in for the username and hit enter, to get to the console login screen. From there I proceeded to login with my username and password, no problem! I used 'passwd' and 'dscl' to reset my password, both of which worked w/o problem. I can do 'dscl . authonly <myusername> <mypassword>' and it doesn't give an error. Despite that, I still couldn't login via the Login Window.

I tried moving the /Library/Preferences/DirectoryServices folder and killing the DirectoryServices daemon so it would restart. That resulted in my password being instantly rejected with no pause when trying to login.

I've also booted from the DVD to reset my password through the utility, repair my home permissions & ACLs, and used the Disk Utility to Repair Permissions on the drive. No use.

I'm really at a loss for what to do now. All my Google searches lead me to instructions for how to join Active Directory from the command line, but I don't want to do that. It doesn't look like it's trying to authenticate to AD any more any way, because the ActiveDirectory plist didn't get recreated.

Help?