Excellent timing! I am currently planning a move to a SAN environment and have been using the "best guess" model to plan the volumes. It's nice to finally be able to document my needs and I'm sure that this will also help my case when I submit my justification to the purchasing department.

BTW: Suprisingly, my "best guess" was only 10GB over the calculated estimate: mine - 750GB, calculated 739.251GB.