I know this topic well, because I work for a Web hosting provider that manages hundreds of remote Windows NT and Windows 2000 systems. For Windows 2000, the built-in Terminal Services in Administration mode works fantastically. It's better for server management than any of the available third-party tools, Microsoft supports it, and it's free.
That takes care of OS-level management but you're still out-of-luck if there is a critical OS or hardware failure. For OS failures, it's helpful to implement remote power cycling gear (RPCG). RPCGs allow remote administrators to control individual outlets in a power strip so you can cut the power to a system and restart even if Terminal Services are not available. Most major server vendors provide similar functionality as an optional add-on to server products.
This was first published in April 2001