It's 2TB with 4 drives maximum any way you cut it, 4x500, 2x1000, 2x750, 4x400 . . . With the Deskstar 7K1000 having a SRP of 399.00, four of these would make a nice 3TB RAID5 storage volume; but not with the ICH8R as the RAID controller.
I have been unable to confirm if the ICH9 family will...