Most home routers, however, (D-Link, Netgear, Linksys, etc) have firewalls and lots of protection built in for the average home user. A combination of a home firewall/router, software antivirus and antispyware and non-MS software should eliminate 99.9% of viruses you will encounter
And you can use virus checkers with OE and IE and other MS products but the vast majority of viruses are aimed at those softwares, so you're better off using an alternate, not to mention in the case of Firefox and Thunderbird, they're actually better