Originally posted by: slashbinslashbash
Not necessarily -- I ran a simple home network for years with just a switch. You just have to assign all the internal IP addresses manually, or set up one of the computers to be a DHCP server. Of course you will also have to configure one of the computers to be a router to the Internet. It's pretty easy with whatever OS you have (under Windows, it's "Internet Connection Sharing"), but you will need two network cards (one inward to the internal network, and one outward to the Internet, i.e. the cable or DSL modem).
Basically it just depends on how technically oriented you are and how much effort you want to put into it. It's really not that hard, but routers are usually "plug it in and it works" simple. Using a switch obviously requires effort and knowledge on your part above and beyond what a router would require.
BTW: This is pretty hot, thanks OP, I'll check my local WalMart.