I have 6 1tb WD blue 2.5" hdd's running in my (dirt cheap) media centre, they are all stacked together ( i know its not good for them at all) I got them as external hdds for $50 and ripped them out
5 are running off sata (no raid) and the last I've used a USB 3.0 adapter and pluged it in via USB ( the mobo only has 6 sata ports and one has the DVD drive)
Each drive is loaded up with software and movies and one is used as a backup for work projects
I've got this setup because I bought the drives over the span of a few weeks and didnt want to format and set up a raid config with drives that aren't really meant for it
I'm saving to buy some more reliable raid drives (maybe WD reds? ) and then ill add them to a raid using a 3ware AMCC 9550SX-12 that I have ready to go
And my laptop I've got a ocz vertex 3 256Gb and in the optical bay I have a 1tb WD blue for all my media and work projects i did this because I want fast boot times and quick application load times