After some very scary run ins with the spyware/malware tricks online recently, I have decided to reconsider User Account Control (UAC). In the Vista Control Panel/User Accounts\User Accounts (yes, that's twice), you can turn UAC on or off. I now recommend turning it ON and commend Microsoft for making this available. It is basically a confirmation of whether or not to install software on your computer. It is a minor annoyance, but is worth the extra typing in of Administrator level account credentials.
At one point recently I was searching Google online for some type of Exchange related issue. I don't remember the exact details but it was some general Exchange server related terms being searched. The 4Th result that showed up (meaning the miscreants paid Google for it) was a Geocities web site, which I felt was a bit out of place, but by the time I thought hard about it, I was being prompted to install anti spyware software in order to remove spyware software that only exists if you follow through the install: in sum, you install their software, they then classify it as spyware and then you send them $20 to fix the problem they created. Clever. Luckily I was aware of the scam. The immediate fix is to kill all instances of Internet Explorer (Control/Alt/Delte then Task Manager processes). But I know many people were not aware and followed through. The install creates a hellish problem.
If anything, UAC being turned on would give people a little extra time to think of the question: do I really want to install this? That is always a good question users should ask before installing software.