Just bought a 500G Caviar drive to replace my nearly-full C:\ /XP drive. Supposedly the CD is bootable, at least it says it is. We tried it in two running XP machines and 3 running linux machines. Not a single boot, even though the CD drive has boot priority.
Since the current c:\ drive is nearly full, it was impossible to install the WD software, and there was no option to install it on one of the other drives, on which there was plenty of room.
Neither Acronis nor Ghost claims to be able to transfer a working system to a new drive/machine. Surely upgrading to a bigger HD is NOT new technology, and I would hope that the manufacturers of HDs would know how to do it. Apparently this isn't the case.
Just one more reason to choose linux, but since there are way more users of Windows, you'd think that upgrading to a bigger HD wouldn't be such a monumental -- probably unsolvable -- problem.