Wired will be much more reliable and faster than wireless. I wouldn't recommend connecting workstations wirelessly in an office environment.
As far as hub vs switch, I don't think either one should require any configuration. As stated previously, a switch gives better performance, though with only 6 PCs on the network, congestion shouldn't be a big issue. A switch will also increase security by preventing someone at one PC from using a packet sniffer to see traffic destined for another PC on the network (emails, password, etc) if you're concerned about something like that.