As stated above, this topic has already been discussed recently. If you do a search, you'll find it.
One point to keep in mind is that it's simply professional and courteous to write a thank you note (not necessarily to everyone, but at least the chair or PD). As the goal of applying to residency is to get into the best program possible, it is easy to think in terms of what is and is not to one's advantage in the process. However, try to keep in mind when you apply to these programs that you are speaking and interacting with your future colleagues. Even though you'll only end up in one program, you never know when you might be working with people from other programs, even the one's you couldn't stand. Just a thought....🙂
