Just doing some cleanup and noticed that in my Write page, under the custom field drop-down, there's en option for:
_ezstatic. This is for the plugin EzStatic, which I had installed a long time ago but have since deleted.
Looks like it's left itself in my database. I did a search in MyPhpAdmin and found "ezstatic" listed in the table wp_options. Think it's safe to delete it?