My question to you would be, is this a list of all the servers (SQL, Exchange, file share, etc?) If so, then it's going to be tough, regardless, to keep a list up-to-date.

You can look into third party tools (Microsoft System Center comes to mind,) but even there, it won't be perfect. It may not track information you want / need tracked, or it may not "find" all your servers.

Any such listing needs for people to make a concerted effort to maintain it and keep it up to date, or it just becomes so much more junk information.

With that being said, we keep track of our servers with an Excel file, so don't feel bad.