I have tried them all, and I find Kaspersky to be the best. Bitdefender (I'm using now) which has better heuristics, has many small flaws in it's design, like I can't turn off the computer after a scan unless set in the scan settings, it blocks your private information without allowing any exceptions that are not programed in, ect.
You are the best anti virus you have (need). I don't have anti virus installed (I never had) cos I don't need it. Viruses (or any other malware) can't download and run themselves. You are the one doing that so just be a little more careful and little less naive (avoid freelotto, "you won!!!" ads and stuff like that) and you'll be just fine.
This is untrue, viruses can download and run themselves but exploiting flaws in your browser, or it's integrated technologies easily. No amount of caution can keep you from downloading an infected file, which was may have been uploaded by a legitimate person who unknowingly has a virus infecting his computer. Not to mention you can't use flash drives, or open emails, which can also easily transfer malware.