I use a hardware firewall and only online scanners. No active antivirus, because I can't think of a time when I've ever caught anything (tried eTrust, Nod32, and Kaspersky).
That will work if you don't accidently visit any dodgy sites and keep Windows updated and if you're the only user of your system. However running without active antivirus isn't something for all systems especially multi-user systems as there's no way of knowing what other people do on a system, or what websites they visit - and remember evil sites like myspace.com which infected people via an ad banner (if I'm remembering correctly).
That will work if you don't accidently visit any dodgy sites and keep Windows updated and if you're the only user of your system. However running without active antivirus isn't something for all systems especially multi-user systems as there's no way of knowing what other people do on a system, or what websites they visit - and remember evil sites like myspace.com which infected people via an ad banner (if I'm remembering correctly).
Well I don't browse/use MySpace (or any other social networking site), I stick to private bittorrent networks (which accounts for porn as well), and I use Firefox.
I do occasionally use online scanners, but only when something suspect happens (like that Earthlink baloney I posted in Spyware Hell - HJT).