Though HD DVD and especially Blu-ray are still out of the price range of most consumers, they are dropping fast. Naturally, as the cost in both the drives and media falls, the interest in recordable media will pick up along with rewritable media. Both Blu-ray and HD DVD camps will soon have rewriteable media offerings. Quite pricey at first, "BD-RE" and "HD-DVD-RE" discs are expected to go for about $10 a pop initially, with capacities of 25GB and 20GB, respectively. Not as behemoth as the highest-capacity HD media that approaches and exceeds 50GB, it's still a lot more than DVD and will likely soon increase.
With the huge increase in capacity that the newer optical media will have, rewritable media may see more use in things like DVRs, where magnetic disks currently reign supreme.