It really depends on what resources you share over the 10 user small network.another thing is security issues.
In you case as I read that you are only sharing a print server or utolizing a print server for a fact is not a wise decision to install a Server OS.
A windows 2k pro is suffecient enough to share the print resources of the entire peer to peer network.
If you are looking for an answer that points out the difference between Peer to Peer computing and Client Server computing. The major difference is the Administration characteristic and autority level. IN a peer 2 peer environment. all node are administrator of their own LSD in win2kPRo. Each of the 10 node use account and password has to be created to all of the node to obtain access to resource that each offer. I Client Server environment it is only the server or the domain controller for a fact that handles all the authentication. e.g. logons, permissions to resources and files., and other services that a Sever OS might offer. You only create the user accounts in the server once and logons are authenticated by a central computer. I beleive this is not new to you. Probably oyu are just confused.
I hope you look closely at the need of your small network before you decide to upgrade or switch computing environment.
Remember what confucious said:
DO NOT KILL A MOSQUITO WITH A CANNON.
Swordfish