I don't run a virus checker; I do run a software firewall, and my 5 PCs are behind a router. I have zero infections on any of the PCs I have running at home. That said, I don't download from sites I don't trust, I don't use IE or Outlook, and I delete "Hey, Take a Look at This" emails. Basically, the precautions that anyone should take (don't eat found food, don't have unprotected sex with multiple partners, don't leave your keys in the ignition) metaphorically apply to the internet.
Even if you DO feel the need for multiple layers of protection (which, by the way, usually turns out to be the real performance killer when these various layers don't play nice with each other), even bargain priced PCs have more than enough horsepower to outrun even a fiber line.
An ATA-100 hard drive has a 100 megaBYTE per second transfer rate; you'd have to be supremely lucky to have a DSL line that exceeds 3 megaBITS/s, or 0.3% of the maximum hard drive transfer rate. Even a high end FIOS line can only supply 35 megabits/sec, or 3.5% of the hard drive transfer rate.
The real performance killers are not evil spyware; it's cluttering up your PC with "trusted" conveniences like RealPlayer, QuickTime, and CD- recorder "helpers" that sit in your system tray consuming memory and CPU cycles waiting for you to finally play a stream or burn a CD.
It's printer drivers that instead of being designed to optimize the printing process, contain drivel like voice prompts of "Your document is printing now" (in case you missed the desk rattling as the $29 inkjet printer that requires $49 ink cartridges blows a dollar's worth of ink while consuming all the CPU resources, because the manufacturers don't put any intelligence in them).
It's operating systems that require 50 separate processes "just in case" you find the need to perform remote program loads from a server that encodes all its pages in Mandarin.
Go ahead, but make sure you know what to be offended by.
According to a 2004 article in USA Today, "Symantec, McAfee, Internet Security Systems, and Trend Micro grew from nothing to a combined market capitalization topping $24 billion by supplying anti-virus software to a hungry market."
With that much money to be made from the fear of virii, is it any wonder that we're all being conditioned to be afraid of them?
Even though your credit card is most at risk when handled by a minimum wage waiter in a tourist trap restaurant, we are constantly bombarded with warnings about cybercrime. Here's the news: it wasn't a virus that "lost" the SS#s of hundreds of thousands of soldiers and veterans; it wasn't a trojan horse download that encouraged a for-profit data vendor to sell personal records to organized criminals.
Save your outrage for the Credit Bureau Troika who continue to convince their pocket congressmen that we "want" 50 credit card applications to show up in our mail each month, that having to wait 24 hours before issuing you a line of credit at BestBuy would be like burning the Flag, and that 24% interest for "universal default" isn't usary.
--Gene