A defense attorney explains why you should always take the fifth. Its an interesting, entertaining 25 minute you-tube video. Here is a summary of the major themes to the video:
1. The fifth amendment was designed to protect the innocent, not the guilty. Don't feel bad about invoking your fifth amendment rights.
2. Talking to the police when you are a suspect can never help your case, but can hurt it. In other words, declarations of innocence can never get a person off of the hook. Statements can, however, be used against you.
3. Even the truthful statements of an innocent person can incidentally make a conviction more probable. It is best to say nothing.