First time I used Vista I could not stand it!
It was a 32bit ultimate something or other on a fairly snappy laptop. It sure was pretty - but a lot of the software I used under XP Pro would not run (older versions of adobe products mostly) at all.
*Newer versions do not have this conflict as far as I know, but I do know taht I didn't want to buy new software.
So a year or so goes buy and I go out and buy a new PC with the intention of wiping the drive to get rid of Vista and stick with trusty XP Pro; but it turns out this new rig is a 64 bit quad core so it is not the same Vista.
So far the most tricky thing I have had to figure out is how to fix active x controllers missing for Apple's Quicktime player.
I found that information here:
http://www.windowsreference.com/windows-vista/fix-for-quicktime-error-46-could-not-find-or-load-activex-control/
Before that - anything that did not run was easy enough to fix by simply disabling the desktop composition when a program starts:
go to C:\Program Files (x86)\what_ever\ and right click on the program and under compatibility check "disable desktop composition or similar