I've heard that some interviewers make you log in to Facebook and show them your page as you see it, so locking it down to friends-only (which is a good idea in general) wouldn't necessarily help with that. Some people have two pages--one for friends, under a nickname, and one for employers, with their full legal name.
Recently, a former co-worker I'm Facebook friends with posted about an event in his life, and his friends (whom I don't know) responded with very risque and rude comments that I could read. Even though logically those comments should be no reflection on me, I wouldn't really want someone else to see them, if I felt my job hinged on it. I mean, the employer doesn't know I don't know those people, right? So maybe there's something in the settings that can be adjusted, so that the only people whose comments can be seen are your friends, whom you have vetted.