Blue Ray and HD-DVD; Amazon S3 storage
I am more excited by Amazon's S3 storage system because it fills a real need that I have for secondary (backup) persistence for web applications. I like to develop close to "no maintenance" web applications. Part of the solution is to use managed hosting (I favor Xen based virtual servers for low cost and good performance) so your web application can be swapped to another server (along with your complete virtual OS environment) when hardware fails. Amazon's S3 service fills the need for incrementally backing up user data "off site", and the price is low assuming you do not need too much storage or bandwidth.