Uh, can you provide proof that F-Secure is "the best"? Or how about Norton? I missed the last study that proved F-Secure is the best.
You guys need to realize that there is no best or worst. It's your opinion, which is fine, but when you state your opinion as if it's fact, you both mislead others reading your post and start flamewars. Not a good thing to do on most message boards.
As I see it, some people have had problems with Norton AV under windows XP, others have had not, some people have had problems with Norton updating, some have not. Some have had McAfee miss viruses. Apparently no one has had a problem with F-Secure or Kaspersky's product, but it also appears that there aren't nearly as many users of these products.
So take that as you will, and realize that you most likely will not go wrong with any one of these.
/Lactic