I started with Norton Antivirus, but recently switched to Kaspersky because of the better features.
My sister always said she didn't need programs like this until she recently caught a Trojan. Your hard drive had to be removed by an expert in order to be able to save the sensitive data on it. We then searched online for good virus programs and had difficulties finding the right one from the huge selection ...
She got me this helpful article recommended, after which we both opted for the Kaspersky version. We can only recommend it!