Well, first off, you can go mixed, having some of the computers use ethernet (wired), and the others wireless.
As far as the setup goes, it would look like this:
--E-- ethernet connection
Cable Modem --E-- Linksys Router --E-- Wireless Router & Junction Box
Then, as a second step, you could run
RJ45 Outlet --E-- Switch --E-- iMac, work PC, and laptop
-t