I prefer to use a router for a few reasons
1. It acts as a firewall and can be used as a DHCP server, and it already has the capacity to serve a few pcs.
2. Its extremely easy to configure and use, and unlike ICS and DCC it doesn't require a host computer to be turned on. After all why have 2 PCs on if you only need to use one?
3. Most routers allow various configuration settings to block alot of sites and time of day and the such alot better than Windoze.
4. If you get on with a built in print server it will be alot easier to share your printer than to have it hooked parallel to one machine.