Here's a tip, in case anyone else has noticed this irritating gremlin:
I built a fresh instance of WinXP on Fusion 2.0.5 after upgrading to Snow Leopard.
I noticed something really annoying: every 30 seconds my Outlook 2003 window would flicker three times. This refresh was very visible and very distracting.
I traced this back to the spoolsv.exe service, which was spiking CPU usage every 30 seconds along with the TPAutoConnect.exe service. Further analysis showed that this was being caused by Fusion's printer mapping function (Settings > Printers > Enabled "All printers installed on the Mac will be automatically added to the virtual machine."
I disabled that setting and the flickering went away.
