A few days ago I found a thread at OrigamiProject forum with a some registry keys that according to the author could speed up Vista a little bit in our devices.
Here are the two keys that needs to be changed:
HKLM\System\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters\
Change EnableSuperfetch from 3 to 0.
HKLM\System\CurrentControlSet\Control\Session Manager\Memory Management
Change DisablePagingExecutive from 0 to 1.
You will notice a good improvement in Outlook 2007 and other applications. If you want to know what every key does and some tests result, check this thread.
Warning: Do no apply the second trick unless you have at least 1Gb of RAM.
Update: James Kendrick tested this hack just reported that all his issue with HDD trashing without reason has disappeared after applying this hack. In another hand, I just prepared a VBS Script to apply this hack.
Updated 2: Kevin is reporting that when the page excutive is disabled his Zune skips 20 seconds before the end of each song.