5 computer network - Windows XP pro vs. Windows Small Business Server 2003

[stanlaw1000]

I have a 5 computer network. I bought a "server computer" (big hard drive - smallish ram), that didn't come with an operating system. I am debating whether to put XP Pro on the server and letting it configure the network, or installing Windows Small Business Server 2003. Since it's such a small network, I'm thinking I could use the sever computer as both a server and one of the operating computers in the network. If I install SBS 2003 on the server computer, will it run regular programs like word and excell? Also, is there a big advantage from a network standpoint of having SBS 2003 run the network as opposed to XP Pro? Thanks in advance. I appreciate any help or suggestions.

[Dark_om3n]

I would go with winxp pro if it should only act as a fileserver, Though I dont know if you are connected to the internet and want the server to act as a firewall with NAT etc.. if so I would go with the server version.