Jimmy May has compiled a great white paper on Disk Partition Alignment Best Practices for SQL Server along with Denny Lee
This is a must read for anyone configuring a disk subsystem for SQL Server.
Jimmy must be going for an award for good performance blogging articles along with two other good references
DMV All Stars http://blogs.msdn.com/jimmymay/archive/2008/10/30/drum-roll-please-the-debut-of-the-sql-dmv-all-stars-dream-team.aspx
Wait Stats Introductory Reference http://blogs.msdn.com/jimmymay/archive/2009/04/26/wait-stats-introductory-references.aspx