External Storage

Working as a videographer I tend to need massive amounts of external hard drive storage for my computer.  For the convenience of my customers I archive their projects for at least one year, sometimes longer.  Needless to say  two 500Gb drives can't do the job on their own.   My first 500Gb drive is a Lacie.  I have yet to have any problems with it and it has ran smoothly for the last two years.  I use it strictly for iTunes (currently at 200.62 gigabytes) and dmg file backups.  The only thing I worry about with my Lacie Big Disk is that one of the 250Gb drives inside will fail resulting in a loss of all my data.  Lacie designed the storage device to contain two Western Digital 250Gb drives held together in a striping raid.  Although striping raids have their benefits in speed if they are not backed up one could easily lose all their stored data.  My next 500Gb drive is a WD 500 eSata interface drive.  It is by far the most impressive external drive I have ever used.  The eSata interface allows for fast, errorless editing of both standard and high definition video.  The only downfall of it's reliability is that I filled it up pretty quickly.  So I bought two WD Studio Edition 1Tb drives, the worst drives I have yet to plug into my Mac.  These drives are triple interface drives (USB 2.0, Firewire 800, and eSata), but regardless of which interface is being used there is a critical problem with the drive. If the computer doesn't use the drive for so many minutes the internal interface tells the drive to spin down and conserve energy (sleep).  Almost all external drives do that.  The flaw that the WD Studio Edition drives have is that when the OS X interface tells the drive to wake, the drive will spin up and eventually freeze crashing the Finder application.  Yes, I know there is always a work around...I can unplug it and plug it back in when it's ready for use but my issue is I shouldn't have to do that. Now with one of those 1Tb drives nearly at capacity I wonder what kind of drive I should get next.