And your other mistakes were..............
Server failures are annoying and upsetting but data losing is soul destroying so one area not to cut costs is where your data lives.
One thing to never do is to run SATA drives in anything other than RAID-10 or RAID-6. Their reliability is just not good enough and with their capacities being at 2TB and soon 3TB that is just too much data to lose so if you must use SATA drives then use RAID-6.
Next don't use Western Digital drives. Sorry but these are not appropriate for business or enterprise level use. These are great drives for home use and for non-critical situations but until WDC gets serious about providing real MTBF information then I can't recommend them.
By this I mean that WDC will state that their drives have a MTBF of 1.4 million hours but if go to their website and do a bit of digging you get this:
What that says is that while WDC will state there is a MTBF they don't actually really know what the MTBF of their drives are. They create their number by using a combination of how long a component should last with how many drives get returned in a year and this counts the ones that are sitting in my mother's and grandmother's computers. That is madness. A proper MTBF measures not only the failure rate but provides you details on what the duty cycle is to arrive at that value and then and only then are you able to make an informed decision about the suitability of a drive to its use.
I am not saying that WDC drives are bad I'm just saying I wouldn't recommend them for use in an vmWare system or anything with a heavy load and I certainly wouldn't ever use them without RAID-10 or RAID-6 in place.
You saved a few hundred on buying the drives and then spent three days of hell trying to recover your data and for me that isn't much of a cost savings in the end.