Matt Garman wrote:

As for RAID usage (md or hardware): just to be clear, my
understanding is that the biggest problem is that, even if the
desktop drives work fine for non-RAID use, they'll still be
"difficult" in an array.  That is, they take too long to report
errors, and thus get kicked out of the array.

Another important, (from a performance perspective), feature of the 
enterprise drives which will be factor in your setup, is that they are 
optimised for use in a high vibration environment (RAFF in Western 
Digital parlance), unlike desktop drives.

The following illustrates the problem in a somewhat humourous way:

http://www.youtube.com/watch?v=tDacjrSCeq4

While the desktop drives will work, throughput and seek times may be 
compromised due to vibration and resonance effects from many drives in 
one enclosure.

Regards,

Richard