So, I patched last night when I got home from work, and then went to log in this afternoon.
It told me "log in failed."
I exited the game, and tried to restart... except that it didn't. Play was greyed out and ESO was in the background as a process. ESO64.exe to be exact.
I couldn't exit the process, I had to reboot the computer. So far, ESO won't stop doing this, preventing me from even accessing the game's main menu.
What's the deal? First time I've had an issue like that.