keep in mind with a hub you have shared bandwidth acrost all 3 computers, but with a router(with a built in switch) you have full bandwidth to all ports. also even if your router is a home use unit, that only uses nat for firewalling (and they all do until you get in to buisness levels) they will keep out alot of attacks on your network. Pluse the router will make it easier to add anothe workstation later, and if your ip only allows you to have 1 ip, with out paying more, this is a work around untill you can get more ip's (yes i pay for all my ip's)
Kfistorok a switch that does nat is a router.