I’ve seen many different ways to represent rack layouts in the past. The most common is usually it is a simple Excel spreadsheet. This generally works pretty well, doesn’t take much time and makes it relatively easy to represent each “U” of the rack buy using an Excel cell to represent each 1U in the rack. The “fancy” way to do it is to use Visio. In the past I always avoided the Visio route because a) I wasn’t too efficient with Visio, and b) I was lazy and perceived this method to take too long. Now, in a lot of cases we try to do rack layouts for most of our clients when appropriate so sending an Excel spreadsheet was not an option (not a good one anyway).
After doing a few rack layouts with Visio I realized it was actually faster, easier and without a doubt looked MUCH better. The biggest challenge initially was finding all the right Visio Stencils for all of the different components. For the rack itself you can use the generic rack templates built in to Visio or use some actual rack templates from APC and other rack vendors. I like the APC template best for a 42U rack whether you actually have an APC rack or not. So, to save everyone Google time I put together a list of some links to some of the more popular stencils for the major manufactures. Many of the links go straight to www.visiocafe.com which is a great site for finding all kinds of stencils.
APC
http://www.altimatech.com/ncpmfg/index.asp?mfgacronym=APC
HP
http://www.visiocafe.com/hp.htm
Dell
http://www.dell.com/content/topics/topic.aspx/global/products/pvaul/topics/en/visio?c=us&l=en
http://www.visiocafe.com/dell.htm
EMC
http://powerlink.emc.com (login required)
IBM
http://www.visiocafe.com/ibm.htm
Cisco
http://www.cisco.com/en/US/products/prod_visio_icon_list.html
http://www.visiocafe.com/hp.htm
Here is a sample of what the end result can look like.
Front View

Rear View
