I read a story online (where else) about a company that sent out a memo by email telling over 400 people in the organization that they were being terminated or laid off. Not the way a good leader would execute such an awful task. No matter what, terminating someone's employment for whatever reason is not easy. And certainly not a email subject.
Always terminate with dignity and respect, let them know why and what the next steps are going to be. The difficult words "You're fired" or "You will be laid off" should be out of you mouth in the first minute of the conversation. Do not wait, or get onto personall topics - this is all about business. Relate the dicussion to the facts - nothing else.