From extremetech.com:



...Now the company is readying a PC drive that can burn Blu-ray, DVD, and CD discs. It also serves as an HD-DVD ROM drive and, with the right software, can play back HD-DVD movies.

The movement towards shipping combo drives has been a slow process, though it's worth remembering that it was several years before drives capable of burning both DVD-R and DVD+R drives hit the market. The stakes are considerably higher in the Blu-ray versus HD-DVD battle, so there's keen interest among consumers in seeing successful combo drives. On the other hand, primary stakeholders in the format wars—Toshiba on the HD-DVD side and Sony on the Blu-ray side—are probably less happy with the idea.

Hewlett-Packard is planning to be the first company to ship systems using LG's combo drive. HP loaned us a prototype PC with an early LG drive installed for us to test. What we found was a drive that's pretty polished as a playback device, but is still a work in progress on the burner side. Let's take a closer look...
More info on the linked page

These kind of drives (to play CDs, DVDs, HD-DVDs and BDs but to record all except HD-DVDs) would be the perfect solution. Who will want to burn into HD-DVD given the capacities of BD? I am speaking in theory, of course...