Just have to give avast! its props. I know everyone has his or her personal fave, but I've been really pleased with this freebie since installing it last year after finally disentangling my computer from the sticky NAV monster.
The clincher, though, came yesterday. I was having a minor problem, which I posted on the avast! users' forum. After getting nice tries but no really good response, I figured I had nothing to lose by using avast's tech-support e-mail link. I reckoned I'd get no answer at all or a useless one in about a week.
I was shocked -- I actually got a response back in about 12 hours, and it was a good, well-reasoned response, not just some regurgitated "knowledge base" article that I could have found myself.
Wow, a free, good (if occasionally imperfect) anti-virus program with customer service that surpasses that of many paid programs I use. Go figure. I almost feel guilty (but I'm sure I'll get over it).
Update: The guy just e-mailed me again to see if his advice helped. Amazing.