I think people reading this for their own benefit should gather from this that a router and a switch are completely different things used for different things.... a router ROUTES traffic from 1 network to another.... a switch connects computers or nodes together on a network.... if you are having a lan party and not accessing the internet you will just need a switch since you are not leaving your network.
Some cheaper routers you buy at like best buy or whatever have a switch built into them usually.... so to call it just a router isnt right... it would really be a router with a 5 port switch built in. That is confusing to joe consumer so they just call it a router for arguments sake.
So in short for an average home use you probably wouldnt need more than one of those router/switch combos.... but if you are going to be hosting a lan party on top of that you might want to buy a stand alone switch and uplink it to your router/switch.
I think a better argument would be Hub vs Switch, since they both accomplish the same thing but go about doing it differently.
I hope that wasn't confusing.