Software RAID w/ mdadm -- Need Partitions?

[Hal Vaughan <hal@halblog.com>]

I've created RAIDs in the past where I just used the entire drive and  
ones where I created a single partition on the drives and used the  
partition.  It seems that there is no real difference in behavior.

If I'm planning on using a drive for a RAID, is there any reason I  
should create a single partition spanning the entire drive and using  
that instead of just using the drive in its entirety for the RAID?

Thanks!

Hal