To get a jump start, I`ll suggest you read a couple of blog post by some of my fellow MVP`s on the subject.
First thing first, click on this link to read the glossary that Aidan Finn wrote. This list should open your eyes and probably let you have some ideas of what might be possible in this build. (Example: think of the possibilities with the SMB File Cluster for scale out applications, using the new SMB protocol together with a new Hyper-V Cluster. If you`re able to achieve any down time for your VMs in this environment, you`re doing something seriously wrong ;-)
Some other useful links related to the subject.
Hans Vredevoort with Using Win Server 8 as VHD to go
Aidan Finn with Hyper-V Management Improvements
Hans Vredevoort with Testing Hyper-V Server 8 Beta
Didier van Hoye with Windows 8 introduces SR-IOV to Hyper-V
Kristian Nese with Windows 8 and why you should care
To be honest, bookmark those blogs if you`re interested in catching up on all the new and excited features in Win Server 8, and especially Hyper-V 3.0