I use a schizophrenic combination of AVG, Avast!, SUPERAntiSpyware (I can't recall if this one ever detected anything... Bah.) and Malwarebytes with Spybot: Search & Destroy for other programs that are more annoying rather than potentially a hazard. Despite what people say, none of them have tried to kill each other yet.
Also, norton wtf. Why would you even have that in the first place?