Even in a tough economy, some people decide to leave their jobs voluntarily. The employee may make that decision because he/she finds a better opportunity, wants to spend more time with his/her family, or because he/she can't stand the boss (See Worst Boss Stories -- Ever!). But regardless of the reasons for resigning, every employee should do so gracefully. I turned to experts from the front lines and human resources as well as career coaches and psychologists for advice on how to make a smooth transition. Here are their recommendations.