If you've got a pretty powerful PC, browse over to this site and checkout some high def content that is using the Microsoft's WMV High Definition technology to deliver HD with software compression.
Microsoft Windows Media - High Definition Content Showcase

diyAudio.com - audio projects by the fanatics for the fanatics

Here is another Internet Multimedia Delivery server... Unreal Media Server - What's new

The Hathor Media server, allows you to access your personal music collection from any web browser. See it here... Twisted Flute