http://binaryfractal.blogspot.com/2008/02/top-5-insanely-popular-apps-that-suck.html1. Norton Antivirus or any major expensive oneService: Making your computer its bitch in exchange for the illusion of safety.
Theory regarding its popularity: People just don't know how to use computers. They download porn all day, use Limewire, go into crappy sites that makes their browsers a pop-up machine with 50 toolbars and watch Power Point presentation that were forwarded to them with delicious trojans, viruses and backdoors. These people are the ones responsible of making botnets more powerful than the world's best super computers. These people one day get tired of waiting 2 hours for their OS to startup and go and buy the Antivirus that looks professional and serious.
Why it sucks: You're basically buying a virus. Everything you are trying to prevent from happening to your computer because of a virus, will happen to it because of the antivirus. Your memory will die instantly, the antivirus will take over and decide what you can do and what you cannot, your internet connection will be 5 times slower and it is a pain in the ass to disable or uninstall. Basically, you'll make your computer run like the one you have in your garage.
A few months ago a Forbes article was going to come out explaining how one of the biggest anti virus companies got caught making viruses. Obviously it was never published and we never got to find out who did it, but that's all you need to know really. Avoid big anti virus companies. Besides, just like Microsoft and Internet Explorer, if most of the human population have them installed in their computers, hackers already figured out a way around them.
What you should be using: AVG or Avast!. They both have free editions that have all you need. They won't hug your resources or make your computer slower, they update almost daily and have the best libraries out there. You can scan your computer with them and they won't tell you what to do. I've personally infected myself with the newest backdoors and scanned with different antiviruses. Most of the popular ones can't detected newer malware, Avast! usually did.
Update: Due to an barrage of emails from NOD32 fanboys, I've decided to include it as well. It's clearly the lightest antivirus out there but it doesn't update its definitions as quickly and consistently as Avast!.