Norton has devolved into one of those clunky, overreaching umbrella application suites. It's so bloated and autonomous that in my opinion it's giving people a false sense of security; when an app by its very functioning consumes so many CPU cycles and system resources and so severely intrudes upon the user's day-to-day activity, the natural reaction is to shut it down, in part or in full, so you can function. Unless every Norton user has a whole lot of patience, diligence, experience and knowledge about his own security, he is left vulnerable to threats in precisely the ways it's easiest to become a victim.
So what's better? Depends on how you roll, so to speak. If you're a casual user and the PC hasn't become a huge part of your day-to-day affairs, running a single, free, good virus-scanner like AVG Free the way it wants to when you install it will probably cover you just fine, and when you're not going to be at the PC either disable the NIC card or unplug it, best firewall in the goddamn world.
If you do dabble a bit harder and play with bittorrent and share files through IM or whatever with friends, and are getting your money's worth out of your 24-hour broadband connection, you should ramp up to two different virus-scanners and employ them selectively where it counts. You could install AVG and another, like Avast or Panda or ClamWin or BitDefender or Cyberhawk or whatever, and leave scheduled scans up and maybe realtime scanning without much of a performance hit, but making sure to unplug your network connection when you're not there, put both systems on highest alert when you're not there and downloading, and make sure to run full scans on all the infectable files you acquire using both tools before you run them.
Now if you're up another echelon further, and you're into everything, downloading stuff from questionable places, in a position where you might be a target for actual infiltration, you need a dedicated hardware firewall that you can understand the functioning and control of, multiple virus-scanners (still no need to pay; though I'm not familiar enough with others to make recommendations over AVG) whose options you understand and can attend to based on need, something to monitor and control adware/malware/spyware, and a sensibly-secure OS setup depending on your setup and needs. Regular multiply-redundant full backups, constant threat-scanning, thresholding, port/permission/process/signing/registry tools, encrypted storage, secure tunnels and paranoia are all helpful, but do you no real good unless what you're being paranoid about belongs to someone else who's paying you to keep it safe. Scan everything that comes in before you open it; if it's a major install run a full deep scan after it's installed and before you run it; don't even accept emails unless you asked for it or the person told you they were attaching something in advance, use a secure browser like Opera, don't open your files to P2P apps, don't use wireless networking, proxy when you can, and if there's any chance that anyone except you can physically access your rig, lock it down as tight as you can with a dongle, biometric, or other access-control tool.
