I personally use Kapersky Internet Security 7.0 which is getting a bit old. They currently have two later versions (2009, 2010) but I prefer to stick with the old software for as long as they support it and simply get a new license each year for the AV downloads just so I don't have to facetiously learn something new.

I'm not sure if the new stuff is similar but if it is then I recommend it.

Basically what I like about Kaspersky is that it only requires 2 relatively small services to be running at all times and the footprint of both is rather small most of the time. If the AV is updating or scanning then of course the memory and cpu requirements can increase dramatically but most of the time the package is fairly innocuous.

You can give their sales support a call and ask them about their nominally required resources, but most AV packages that I've seen seem to require far more services and memory . Pretty much *all* AV/firewall/etc. suites will allow you to download and try for a limited time for free but I prefer to have a good idea of precisely what I want before I install something simply to "try it out."

Nod32 AV and just don't download stupid things

Standard firewall, SuperAntiSpyware, Spybot, CCleaner, System Restore. Also, Common Sense.

I've had one problem in the last two years. Friend gave me a flash drive and later, about thirty seconds after I plugged it in, called me up to tell me they had gotten a ton of viruses.

I sit in the DMZ without a firewall or anti-virus.

Unfortunately it hasn't been nearly as much fun as I'd hoped it would be, it's been so long since I got to play around in my registry.

If you're not a retard and you keep up to date, it's exceedingly rare to get an infection, and nearly all infections are harmless unless you're the aformentioned retard.  If you like trying to figure out how to get rid of that new fangled virus that no one has fixed yet, the slight risks turn into rewards instead.  Just leave off the warez, block popups and redirects from sites you don't trust, and stay the hell away from email attachments.  If you must use an anti-virus, the only thing you really need to worry about is it fucking the computer up instead of a virus, so go for whichever one is safest.

My GF uses PMS - no virus would dare attack her...

I'll second that.

(MSE = Microsoft Security Essentials)

AVG Free Edition and Spybot Search and Destroy are what I use.  I'm not sure if that's the best there is, but it's the best I can do for something free.

the best way to prevent any virus attack is to be discipline and control your behaviour online. if you know it's an untrusted site e.g. file sharing sites, don't download anything. if it's an email from an anonymous sender, don't open the attachment. stuffs like that. 

All i use is zonealarm and avg 9.0