weblearner I use Macfee and I'm very satisfied with it. I used to use AVG Free version but it occurred that it didn't find some Trojans which were hiding in my PC. Macfee does a great job and is worth the price!
I use AVG and I am happy with it. I have used Avast in the past and it was ok also. I like AVG better. Norton is a hog and does slow computers down that I have used in past years.
in recent tests I did of several well-known anti-malware software programs I found Microsoft Security Essentials to be top notch. It's only been in release about 1 year, so a lot of people don't know about it. Works on Windows only and free.... but the best part is it works better for me than several others mentioned here.
I don't use any, I am a Linux . My wife uses Microsoft security essential. Hard to say whether it was slowing down her machine (core i3). It's free and you can download it from Microsoft.com website.
