I recently turned off Vista User Account Control on my laptop. I'd left it on because I figured I'd give it a go and see whether I could fit in to the new Vista way of doing things. It was when I was clicking "OK, OK, Just Get On With It" on almost every dialog that I realised that this was not a good idea. One of those popups was a Windows Firewall message and I'd not looked to see what I'd just let through.
I'm actually behind a myriad of firewalls and natty things here, so Windows firewall isn't really all that important to me, but the thing that made me stop was the fact that I'd become so used to just clicking my way through dialogs as fast as possible to get on with whatever I needed to be doing that I didn't actually read the dialogs any more. At that point, I figured there was no point in having them there, so I turned them off.
I have left the UAC turned on for Nathan's little machine, for fairly obvious reasons, and I have to say that a basic user who has no wish to do anything admin-related will likely not have as much of a problem with that as a feature, but my dialog apathy has remained, and I have to really stop myself from just typing in the admin password on Nathan's box and attempting to get round the blocks without thinking it through first. His machine makes extensive use of the parental controls and website filters to prevent Google search nightmares (he often plays with the keyboard and could easily search for xxx!)