Originally the only Antivirus software I would ever recommend was Norton AntiVirus, because it was the best that there was. Mind you there weren't really that many competitive products out there at the time.
Now we've got anti-worm, anti-spyware, firewalls and anti-virus software all built in to one "security center". I really really really don't like Norton Security. It gets into all of your network and computer settings, interfering all over the place. The "user friendly" controls are not user friendly if you aren't a computer novice! You try to do anything with the Norton firewall out of the ordinary, its nearly guaranteed to fail. Once its installed on your system there is no way to remove it. Oh yes! It has an uninstaller, but it does not remove everything. It leaves bits of itself embedded in your OS, causing problems with any new firewall software you might chose to use or just with normal networking setting.
Thats not the worst of it though!! I've just updated Norton on my in-laws PC (because I wasn't there to stop them buying it again). You know what it asked me to do before it would install???!!!???!!
It told me that it was incompatible with Microsoft Anti-Spyware and Spybot S&D and they must be uninstalled!!! What???!! Incompatible with probably the best Anti-spyware software available!!! What a load of tosh!! By the way, I am actually talking about the Microsoft Anti-spyware, when I say probably the best. Ole Bill made a good purchase buying Giant. :)
So anyway, not best impressed with Norton, even less than I already was! Don't buy it!! Get yourself PCCillin instead!