1.       Install Integration Services

2.       Uninstall VMAdditions and Compact VHDs

3.       Set Display for Best Performance

4.       Configure Fixed-Size VHDs

5.       Use SCSI Virtual Adapters for Data Drives

6.       Allocate CPU Resources Based on Anticipated Usage

7.       Consider Using Pass-Through Disks

8.       Ensure File Share High Availability

9.       Configure Domain Controllers to Optimize Performance

Detail at Microsoft's Technet Blog: http://blogs.technet.com/vikasma/archive/2008/07/24/hyper-v-best-practices-quick-tips-2.aspx