This entire security paradigm makes a grossly invalid assumption: ordinary people actually know what to trust, that they actually know what they are doing and know how to protect themselves. The vast majority of consumers treat their systems like a trusted home appliance. They assume that it should work and keep working as long as it's plugged in and they pay their broadband bill. They have no clue about how their systems are subject to attack from all sides--they simply trust Microsoft to protect them. Putting the responsibility for their own security entirely in their hands is a truly ludicrous idea.
I just build up a system for my granddaughter (age 5). She was able to connect the keyboard and mouse (color-coded cables) but when we visited a trusted web site that had a PDF file, the trouble began. For some reason Vista does not have the Adobe Reader installed. (Incidentally, one MUST have UAC enabled for it to install.) In the process of getting the file read, we must have had to click "OK" to a dozen (literally) dialogs warning about one thing or another. Try to explain that to an ordinary person--much less a 5-year old.
Should parents expect their children to come and get them when they see these dialogs? How are parents to know which are real threats and which are not? Since the parents or someone they trust told them that it was okay to click through the message, why hasn't the system learned that this action is safe? No, this system is totally, 100% unworkable. Why? Well, people will get so tired of these constant security popups that they will disable the feature and then what? Since the security scheme assumes these attacks will be prevented by UAC, once it's disabled, they're pooched.
I think that Microsoft has really failed the world's computer users--they've had a decades to get this right and they still missed the mark. Frankly, I think it's insane to build better and better filters when the problem is polluted water. MS and the worlds internet service providers need to rebuild the internet so those who have no regard for the law can't prey on the most vulnerable--our wives, children and the elderly. They need to stop talking about fixing the problem and just do it. Microsoft has the money. Just do it. And stop foisting off the job on the consumer.

Very well put. User Access Security has always seemed somehow wrong to me and this summarizes it nicely.
I've used Vista very rarely in Office which was eventually removed because of security reasons. I don't use Vista at home and stick with XP. I get what you're talking about, it's ludicrous yeah! Many still think that Windows is everything while I agree that the power MS has and the potential they've, they can create much better products and do much more on security grounds. Bringing on each OS with so many security holes isn't an answer from a company who claims to be committed to safeguard every windows user. I hope Windows 7 does get everything right for which Vista was heavily criticized.
Regards
Alan Barker (Real Estate Roy Utah)
Vista can be challenging and because so many aspects of the UI are new one can really feel the pain of transitioning. I've installed Windows 7 which will be publically available in October and it seems to work better and far faster. XP is not a bad OS. It's experienced and there is very wide support for it. However, it's also prone to any number of attacks and frailties that can make it hell to work with once its corrupted--and it does not take much to contaminate it. Win7 is far more secure (too secure AFAIAC in some areas) but a better OS for consumers and office workers who don't want to have to deal with security issues all the time. There's also going to be an XP Hosting application available (now in beta) that will let you run an XP "HyperV" emulation on your system to run applications that only run on XP.