Last time we evaluated Mozy and Carbonite for our own use,
Carbonite client application just refused to work on our system (crashed or something like that), and Mozy was PITA to administer. That was a couple years ago, so the things might have changed since, but you'd better check this carefully.
1.Assuming that WD 150Gb raptor is the fastest of all drives I would make one partition on it, and install Windows onto it. WD 74 GB (which has more than 50 reallocated sectors) as storage for the something you do not care about, or for something that can be restored from some other location in...
Try to connect at least one of your disks to another (known-good) computer. This way you can detect whether it is problem with your mobo or the disk itself.