Microsoft Security Essentials in combination with Your Brain does the job just fine.

I've been living in japan too long... i read AV as something totally different...

Hehehe, as a Hongkonger, I know exactly how you feel.

Sorry, my bad, yeah. It could replace your Lavasoft Ad-Aware program for a year, but not really an AV.
It was late-night, and my meds were kicking in...
I'm not suggesting you do actually use it, or even buy it next year : I just thought some people might like to try it, like me. I test quite a lot of software, and hardware, and it's rare you actually find an offer like this without having to Trial-Pay or something....no loss to me either way : At worst, I'll have to reinstall my OS a month or 6 weeks early this time around, if it really FUBAR's the system...

Another Avira user here (happily subscribed for another 2 years due to a stupendous offer).
I saw this offer on Windows 7 release day but decided against it - really, people should be fine if they have a decent AV (Avira or Kaspersky are my choices) and use Firefox along with Adblock and Flashblock.
It's a good offer though and Iobit should be applauded for their generosity, it's not to be sniffed at by less advanced web users.

Avast is what I have used in setting up a lab for a professional/education environment, and use avast home for free at home. It uses the same/similar engine and databases as the big players out there (Norton, McAffee).