Vista’s UAC and the corporate network

Adding a few Vista (Business Edition) systems to our office’s 2000/2003 Server network. The User Access Control (UAC) feature brings up some big challenges. Though Vista still provides for different user levels, any suggestions on the use of the UAC? Unlike XP, Vista appears to require Administrator access to do just about anything. Yes, it is a good security tool, but it is a little inconvenient for regular users. With the UAC disabled, does the Administrator account become obsolete?