Proper setting for user account control?

[grinding4$]

Can someone please tell me what the recommended setting is for user account control? I was of the understanding that having it turned off was preferable for Vista, but not for XP or Win7.
Also, if my archived hands are on a different hard drive than the rest of my HEM stuff, then will it be necessary to turn off user account control to keep from running into admin issues coming from my OS?
Thanks in advance for all helpful replies.

[Patvs]

Vista/Windows 7: recommended is to just turn it off.
XP: the user already has admin privileges and you don't have to change any settings.

Note: UAC is really annoying for bringing up those popups "are you sure you want to start/install this program" "are you sure you!?" usually asking TWICE when all you want to do it start/install a simple program. Turning if off gets rid of those messages