Personally I've have gone through most out there over the years. Now I use Bitdefender Total Security, though if you don't like the idea of actually having to renew the subscription every year (or three) then you might want to consider http://www.vipreantivirus.com/
which if memory serves is actually made by the people who made Bitdefender, but has the added advantage of offering a lifelong subscription, something like this http://www.ebay.co.uk/itm/Vipre-Internet-Security-2013-1-PC-Lifetime-Subscription-PC-NEW-/290938145705?pt=UK_Computing_Software_Software_SR&hash=item43bd43cba9
which can work out much cheaper in the long run. Oh and have things like Spybot and maleware antibyes installed anyway, they can either stop some things starting altogether (spybot) or can find somethings normal antiviruses miss.
Oh and a quick edit, if buying Bitdefender, buy the earliest version you can find (like 2010/11), you will automatically be upgraded to the latest edition, and normally save yourself quite a pretty penny.