The theme files of my sites ( http://upmarketnewsletters.com and http://endometrialcancer.org ) were trashed and I had to restore them from my hard drive. The database wasn't touched, just the theme files. This was a deliberate action: whoever it was had inserted a spam link to a spam site into the homepage's theme files, only in the process they apparently wrecked theme so that it wouldn't show (I think they hit one of the calls to one of the plugins).
Anyway, I'm assuming this was because I was too liberal with the server permissions. I need the themes to be server-writable for the theme editor. So what is the precise chmod profile I should use for the theme files? I have checked the codex but never found anything.