Rack organization best practices?

I've been tasked with reorganizing one of the racks in our data center: I'm going to pull everything out, re-cable everything, move servers up and down as necessary, etc.

I'm looking for best practices for rack organization, but my google-fu is failing me. I'm looking for ideas on how to put together a clean, easy to work with rack. Specifically, here is what I'm looking for:

• Switch placement. Top, bottom, middle?
• Does it matter where servers of different sizes are placed in the rack? We've got some 2U servers, some 1U, and a 3U SAN.
• General advice on cable management.

Other things of note:

• The servers in the rack are relatively static. There won't be a lot of pull-this, install-that going on.
• Airflow isn't much of a concern.
• It's a four-post rack.

Thanks!