Blue Ray is already in stores now, and the technology like all previous types will become more affordable as time goes by, but let's get to the main point here...your normal DVD has a capacity of 4.7GB, where Blue Ray has a capacity of 25GB. Which would you want to have to back up a 200GB hdd?
This isn't going to be a flash in the pan, it's going to be here for a while, at least until Holographic DVD technology becomes available, this will provide a DVD with a capacity of 1.6 Terabytes.