This sounds like a good deal if you order a number of discs, especially for the Harry Potter giftset. Plus, I only have the xbox 360 HD-DVD player which doesn't do lossless audio.
Anyway, I was wondering about the quality of Blu-rays vs HD-DVD for some of the discs. Are Planet Earth, Superman Returns, and 300 all good on Blu-ray? However, I am not sure if I want to bother with Superman Returns since the movie was blah... Also, I think a special edition of 300 is rumored to be released on Blu-ray soon? I might just transfer over Batman Begins, Harry Potter gift set, and Planet Earth.
One disc that was odd was Blade Runner - why is the upgrade $15 when you can buy the Blu-ray disc for $25 off Amazon.
Finally, I would love to upgrade the Ultimate Matrix collection, but the deal sounds like you need to have kept the flimsy piece of paper that was attached to the boxset via a small thing of puddy.... Who actually keeps such pieces of paper? ;p I always throw those away - it just sounds like Warner doesn't want to trade in that release...