Vista User Access Control
The Vista User Access Control (UAC) is an awesome feature that keeps you safe and secure as you make changes to the system. UAC was implemented to make sure that you knew what you were doing before making changes. For example, the UAC may prevent you from installing an application unless you reenter your admin password. This is what Apple's Mac OS (based on UNIX) has had for a while now but is being well received on Microsoft's newest OS.
My only complaint is when setting up a new install of Windows Vista, you're stuck with constantly clicking through screens, entering your password and telling Microsoft that, "I'm sure I want to move this file from its original location." I don't suggest users perform daily duties with the UAC turned off but while you're setting up a new install, its easy to turn this feature off. In the Control Panel, browse to "User Accounts" and click, "Turn user account control on or off". Restart and enjoy!