I've never used XDCAM disks, but I've heard of people storing masters on them similar to HDCAM and Digibeta tapes.
But this is probably the most expensive form of storage you could choose. LTO5/6 will be much cheaper if you're storing a lot of material. plus, LTO allows you to store any data, whereas I believe XDCAM disks can only store XDCAM video (but I could be wrong about that)
I agree, buy an LTO 6 drive, use LTO 5 media on it. You are looking at approx 30 dollars U.S. for 1.5 TB worth of storage. Last XDcam i saw was about 20 dollars U.S. for -what- 23 gigs?
I've had my LTO 6 drive for about 9 months now, and the tapes for it (2.5TB) have dropped from 120.00 to around 60 dollars so far. Still makes the LTO 5 media a better cost per gig, but as the prices drop...