http://www.facebook.com/settings/?tab=privacy
Sharing on Facebook (Custom)
Choose Your Privacy Settings <> Customize settings

Things I share

Posts by me
Friends only

Family
Friends only

Relationships
Friends only

Interested in and looking for
Friends only

Bio and favorite quotations
Friends only

Website
Everyone (if you are promoting someone else's website on your profile) or Friends only (if you only have your own personal website URL)

Religious and political views
Friends only

Birthday
Friends only (or only-me, if you are paranoid: social security numbers can be generated if this information is known)


Things others share

Photos and videos I'm tagged in
Friends only

Can comment on posts
Friends only

Friends can post on my Wall
Enabled

Can see Wall posts by friends
Friends only


Contact information

Mobile phone
Only me (or Friends only, if you are not paranoid)

Other phone
Only me (or Friends only, if you are not paranoid)

Address
Only me (credit card offers can be solicited and social security numbers can be generated, if this information is known)

IM screen name
Friends only

Email
Only me (or Friends only, if you are not paranoid)


Choose Your Privacy Settings <> Applications, Games and Websites
Game and application activity
Friends only

Info accessible through your friends
NOTHING CHECKED (except website, if you are promoting someone else's website on your profile)

Instant personalization
Opt-out (ALSO requires BLOCKING certain applications: Pandora, Yelp, and Docs - see below)

Public search
Enabled (unless you want to stop receiving friend requests)


Block Lists
Blocked applications
Pandora, Yelp, and Docs at a minimum in order to disable "Instant personalization" (see above, Applications, Games and Websites)

*Blocking an application is the only way to absolutely prevent facebook apps (and the new "instant personalization" websites) from gathering any/all personal information about you, regardless of other settings.  Blocking farmville, for example, prevents the farmville status updates of others from infecting your newsfeed, as well as removing farmville's ability to discover information about your friends and any other information you yourself share.




Summary:

Make sure you successfully block the three apps that i mention in the block list section, turn off instant personalization and remove all checks next to info accessible through your friends inside the applications, games and websites section. These are the top 3 items that are easy to miss / not get correct.