Classroom Expectations?

In planning my first week of the school year, the question always arises: How soon must one set expectations for the classroom? And how does one go about doing that?

I think I'm going to try a couple of different tactics this year. With my first class, I'm going to leave expectation-setting until the beginning of the second week (fourth actual day of class) and pack the first week full of getting-to-know-one-another activities. I'm hoping that if we all become fairly comfortable and trusting of one another, expectations will fall into place. On the first Monday, I'll ask for ideas of expectations from the class, but will be clear on my main two:

1. Respect all people and things in the classroom at all times.
2. If you do anything that bothers me, I'll tell you to stop and you will. :)

With my other class, I'm going to brainstorm expectations with the class as a whole on the very first day. We'll narrow it down to about five total.

This should be an interesting experiment in classroom management and behavior... Any ideas out there on what works and what doesn't?