There was an older topic about this, but it's pretty outdated so I am making a new one.
I've done a bit of research myself since I want to switch. I love NOD32 2.x, but they are shutting down support in February so I basically have to get something else. Even though AVG seems to be often in the higher rankings on the top lists, I don't like it. I've once tried it and it was really weird, detecting a lot of false positives (especially modified executables aka cracks). I've also heard of a lot of people similar things. Personally I wouldn't recommend it. In comparison Avast is apparently good, but I've also heard my share of rants about Avast. Another one that a collegue at work recommended was Avira. He says he's quite satisfied so this is one of my two top choices. My other top choice is Microsoft Security Essentials. If you have a legal version of Windows (yay, I do), apparently Microsoft's own software seems to be working well. I remember back in the days *gets ranted on by Dr. Cox for that* Windows Defender was an utter piece of crap, but I've heard a lot of good things about MSE and even a friend (and collegue at work) of mine uses it and agrees that it's working well.
Basically my personal recommendations are Avira and Microsoft Security Essentials (if you have Windows legally). What are your experiences and recommendations?