"I like the idea of being notified if a change to my computer is about to be made. I like it alot !!"
djwayne, UAC cannot differentiate between good stuff and bad stuff. If you wish to download an application, you give permission to "make a change to your computer" regardless of what malware may or may not be attached to it.
How can you be assured that some malware is not being passed on to you without you or the sender knowing that it is attached to a legitimate download? When you give permission to download an item, neither you nor the useless UAC knows with certainty you are going to get exactly what you want, all that you want and only what you want. Such a large percentage of malware comes to you attached to documents...