The biggest problem I see is that you are buying cheap crap drives from Best Buy.
#1 rule for power computer users: don't buy from Best Buy.
#2 if you are going to buy a new hard drive, buy an ENTERPRISE CLASS hard drive - a good clue is if a manufacturer has a 5-year warranty on it, they are building it to last. Seagates are fine, WD's are fine - just buy the higher end drive lines and not the cheap crap they put in Best Buy.