Dawn Dugan specializes in writing books, articles, white papers, reports and special communications for the human resources industry. She is the co-author of Effective Executive Compensation, which was published by AMACOM in 2008. Read more...
If there's a desk or table separating you from your interviewer, this will take care of itself. Otherwise, be sure to put at least two feet between you and the other person, but not more than three feet.
Sitting too close, or touching your interviewer aside from the handshake--a jovial punch to the arm or a touch on the shoulder--is completely inappropriate.
Not to mention no one likes coffee breath, so keep out of the other person's personal space.