WP-SUPERCACHE ATE MY WEBSITE! - It's EVIL!

Whatever you do, BE CAREFUL if you are using the WP-SUPERCACHE Wordpress plugin..

I'll explain the problem: My site was having speed issues, so I investigated alternative cach plugins. I settled on Quick-Cache.
So, I disabled Supercache, which then argued, in BIG RED LETTERS at the top of the dashboard, and advised me to visit it's settings page, as caching was off. I didn't want to do that, so I hit "deactivate" again.

BANG!. The site was dead. Not only that, but it was displaying the contents of the WP-CONFIG file in plain text on the frontpage!!! Including database login details, password, etc.. DISASTER!

I was heading home on the train as all this was unfolding, so I got the support guys at Unlimited Web Hosting to shut down the site, which they did, instantly.

We then spent most of the night, on and off, trying to get the site back up.
Unlimited showed me a neat trick to disable all Wordpress plugins without access to the site.. I'll be posting about that later..

Anyway, I decided that wp-supercache had corrupted something, probably wp-functions, so I reloaded Wordpress over the existing files (after configuring wp-config).

Jackpot! The site came back up. I then re-enabled the plugins, one-by-one. (they were all disabled from earlier).

DELETED WP-Supercache, and installed and enabled Quick-Cache.
I suggest you do the same.