Believe me I've found that out the hard way, but in truth I've had relatively few problems and only 2 that have not yet been resolved; Quickbooks and the E220. Everything else has worked fine and for the most part I'm really enjoying Vista.
Thanks for all the help and my apologies for stepping on anyones toes, I'll try the fix as described and give my feedback.
Hope you get your Quickbooks running .. what you could do as a short term solution is load Virtual PC 2007 (Beta) under Vista. Then create yourself a virtual machine loaded with XP. You can then load Quickbooks onto that Virtual Machine and run it from within Vista. Works perfectly.
I have tested Virtual PC 2007 and it works just great on Vista and is free software. Try it out.
Glad you are enjoying Vista, I really like it, its snappy and outperforms XP on my particular laptop. I know this because it came loaded with XP and once I had loaded Vista the speed differences were remarkable.
Hope you get the E220 sorted out.