Depending on how many people will be using your network, you may or may not want a machine dedicated as a fileserver. If your data must always be available and you cannot afford a slow down or crash of the server, then dedicated is the way to go. There are many other advantages to getting a Network Server Operating System. These include better speed performance, tighter and more flexible security, and more flexible file sharing. Performance with a Network Server Operating System is better than with a peer network operating system largely due to the way the operating system and underlying file system are designed and optimized as well as how memory is used.
Security can include anything from knowing the name of the server to having user-level rights.
For many server operating systems, file ownership can be set on a user, group, and world level basis. When combined with security, file sharing can be more flexible in that, even though an entire disk or portion of a disk is shared, users can see only the portions of the shared space that they have been given rights to see. Printer sharing is similar to a peer operating system in that you can share printers physically attached to a server, printers connected to workstations, or printers connected directly to the network. Some servers can run applications which process requests from local and remote clients. Examples of this could be a database server or a web server.