I never said a single RAID 5 for the database files. Database files (mdf, ndf) will give you best performance for the dollar on RAID 5 arrays. One you start getting into larger databases then I like to start laying this out like this.
C: - OS (RAID 1)
D: - SQL Binaries (RAID 1)
E: - High Performing Database Files (RAID 5) (Meta LUN with 15+ drive behind it)
F: - Indexes (RAID 5)
G: - Database Files (RAID 5)
L: - Database Log Files (RAID 1)
T: - TempDB, ERRORLOG, SQLAgent.OUT, etc (RAID 1)
Depending on the system needs more of less drive letters. I've got a system I'm working on now with 6 drive letters free, and I'm currently working on breaking the single large data file into 9 smaller files on various LUN mount points which will all be attached as folders on the E drive to increase performance without needing 9 more drive letters (which I don't have available).
Check out my FAQ on Disk layouts. Most of this is sovered there.
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration / Microsoft Office SharePoint Server 2007: Configuration)
MCITP Database Administrator (SQL 2005)
--Anything is possible. All it takes is a little research. (Me)