I stopped using Norton years ago because it didn't update the virus definitions often enough, in my opinion. I don't know how it is now. I also feel it's a terrible resource hog, especially the Norton Internet Security suite. On my machines, I use avast! antivirus and Kerio Personal Firewall. You may find that AVG and Kerio Personal Firewall are a good combination for you. That's most likely the combination I would go with.
Whatever you choose, you must make sure that the virus definitions are being updated frequently. Additionally, no antivirus can protect you against all the new/unknown threats for which they have not yet developed protetion. The best protection for that is you. You must be careful not to open e-mails from unknown sources, and avoid clicking on links in e-mails and instant messages. Dubious sites must be avoided at all costs as well as all unknown/unverified downloads.
Whatever you choose, you must make sure that the virus definitions are being updated frequently. Additionally, no antivirus can protect you against all the new/unknown threats for which they have not yet developed protetion. The best protection for that is you. You must be careful not to open e-mails from unknown sources, and avoid clicking on links in e-mails and instant messages. Dubious sites must be avoided at all costs as well as all unknown/unverified downloads.