The registry key if needed.
your suggesting that users use the older tools and manually visit every single registry key that those tools manipulate to take ownership of them, or more precisely, to use the convoluted permissions dialog to add their user to the group of users that can change them? are you INSANE?
Not to mention this involves typing out their specific User name in the form //machinename/username
of course you could completely circumvent to whole concept behind both UAC and Limited User accounts by just granting the permissions directly to HKEY_CLASSES_ROOT.
And actually, the better method with the older tools is pretty obvious- run as administrator. no need to change permissions at all.
As an aside: I was thinking- "doug knox... I've heard that name before" and it came to me!
he used to write a Column in one of the MSDN magazines... I'm not sure exactly which one, but I think it was "Flux". I cannot seem to find any references to this anywhere though...