+1 for Eset, and here's why. I am a security "buff" (eventually looking to go into either IT security or AV programming once I finish my degree) and I have done real world tests of AV products (I have +131,000 real, live malware samples) and my employer was looking to switch away from Avast free. I randomly pulled a handful of samples (from real, actual worms that spread over networks without human intervention to build-a-virus toolkits) and Eset detected everything except for an installer for a registry cleaner (which wasn't flagged at the time by any of the virus total engines either).
However, my employer was interested in the free product in this trial (Eset was the control case...) 360 Internet Security (now 360 Total Security Essentials) which uses 5 different engines (only three are turned on by default).
http://www.360totalsecurity.com/features/360-total-security-essential/