Overall, switches give better performance that hubs. Hubs will pass all network traffic through every port. Switches create a virtual circuit to the destination computer. Traffic does not pass through the other ports.
One switch would work fine for up to eight computers.
I would use the switches as the backplane, so it would appear like hub, switch, switch, hub and then run all the high demand systems (servers and admin workstations) on the switches. Afterward, just use the uplink port from a hub A and connect it to switch A, then likewise for hub B and switch B. After that, connect the switches together via an uplink and now they will behave as a backplane/backbone for your network. Most network vendors support this mentality by offering highspeed options to their switches via custom SCSI-like, fibre, and Gigabit-over-copper cabling interfaces that allow separate switches to be linked into a single large virtual switch.