if you don't use antivirus or antispyware, any claim that you never have been hacked is empty. you could been hacked right now. There is no excuse, antivirus is free. Like Avast Free etc. and the anti-spyware measures I listed don't cost you any cpu cycles in game. Most are just browser security.
well, better safe than sorry, and if you really get hacked, and they got into your DNS Service, you cant access the antivirus and other genuine sites anymore..... and really, why such a big sig?