Could be interesting for experimenting with... could also be frustrating. All that stuff is really only relevant once you start using the machine as a domain controller. Unless you want your other machines fully reliant on it, I wouldn't suggest it for a simple home file server.
Using Win2K will also let you build your server on a lot less powerful machine, since it uses significantly less resources than XP/W2K3S. If you want to play with AD and other server features, find a copy of Win2K Server and get the best of both worlds
