To make a quick point, trying to upgrade to a different audio format from CDs is not at all like the upgrade to HD visuals. HD-quality visuals look quite a bit better on an HD-DVD format if you were to purchase a big screen with 1080p capability. And not only is the resolution higher, but with the added space on an HD-DVD or BD, you can have less information loss due to the video or audio compression. Less compression means better quality. CDs on the other hand already have enough space to reproduce sound in a way where the human ear can't really notice "better" quality.