To make life easy install XP Pro. If you want to play around just keep in mind as the others have said that anything that is designed for server use will not do what you expect for Desktop use.

If you have XP Pro on all your machines then you can net work them together and be able to run each computer from one machine. There is some really neat things you can do with Pro to Pro.

After you get board with Pro to Pro then try using a server OS..

IMHO.....