Norton Antivirus is okay, but Norton Internet Security can be described only with a string of four letter words.

I'd quite fond of Trend Micro PC-cillin. About 2 years ago me and a few colleagues did some side by side testing. Both Norton and Trend products managed to clean up every virus infection, however, Trend nearly always had their update out first. There have been a number of viruses over the years that have attacked and disabled Norton successfully because of this fact.

Norton is a little clunky. Symantec are exceptionally good at buying up good products and ruining them.