Yeah, went in there but the setting was already set for "turn on DEP for essential Windows... DEP for programs was unticked.
OK, the storm has passed and I can elaborate some.
Although the programs DEP was unticked, I ticked it and rebooted... no difference to CPU usage, so I then reticked DEP for Windows, but before I rebooted, I noticed my page file swap was below the reccomended to upped it to the suggested 9211mb and then rebooted, resulting in lower CPU usage... back down to between 2% - 5% on idle. The program that now seems to have it peaking most is CursotFX Plus, sending it up to 9% - 13%... but I can live with that, as opposed to the much higher peaks of before.
One thing I read a while back somewhere was that moving the page file swap on to another drive and providing the path was one way of improving the performance of the OS drive, memory and etc, but I can not see where to do that in the Advanced System Settings, so a tip/heads up on that one would be appreciated.
Genearally, I am very happy that I made the switch to x64 on my main rig, and while the Start Menu All Programs folder hang can be a bit of an inconvenience at times, clicking the 'back' button/closing and reopening the start menu are workarounds that work for me without too much trouble/delay. Besides, my most regularly used apps have shortcut in Workshelf, ObjectDock Plus and of the front panel of the Start Menu, so it's no biggie 'til a fix is found.
I also read that Vista Service Pack 2 will include support for new and old hardware that previously was not compatible with Vista, and in particular x64. That's good news for those considering Vista 64 bit, and with all but the drivers not loading for my new webcam, all my software works seamlessly in x64, so Vista 64 bit has come a long way since x64 in XP and is well worth a try for the additional RAM and system power it utilizes.
*Sorry if I hijacked your thread a little, Brad, but it was all related to Vista x64 and felt it may be useful to those considering the change *