Some good points. However there are a few missing bits of information.
#1: RAID doesn't really mean inexpensive disks. http://en.wikipedia.org/wiki/RAID
#2: Always use "Advanced Format" drives (4k sector). There's no reason to buy 512b sector drives anymore. This will improve your uBER to <1 in 1^15
#3: Nearline (sometimes called enterprise) drives do have one physical advantage over desktop drives. The have an additional vibration sensor (rotation) that allows them to work in sets without the seeks from one drive causing seek errors (harmless, but performance degrading) in another.
These days you can buy very nice low power nearline drives like the WD RE4-GP.