I recently moved to Active Directory and my general user account was diminished from domain admininstrator to standard
user (I got a separate admin account). This means every time I wanted to do some admin work on my file servers I had to log in as my admin account. RunAs works well with some programs but not with Explorer -- you have to log in and out each time.
My tip is to use a free utility called 2xexplorer. It's a great tool which allows you do a RunAs by simply shifting and right clicking in Windows 2000 and Windows XP. Every file or folder you open with this application will automatically be opened with admin privileges so you can edit text files, etc.