I haven't run any antivirus in years and years now on my home computer, but at work we use a number of different ones to disinfect customer's computers. For resident protection I like nod32 or f-prot because of how light they are.. For spyware etc, I like spybot search and destroy for its ability to correct a number of windows settings that get changed by spyware, I like malwarebytes and superantispyware for being able to get the harder ones out, and I like combofix, smitfraudfix, gmer, and rootkit revealer to get out the hardest ones.
The worst antivirus programs I've used have been norton (huge, bloated, takes over everything, doesn't catch or disinfect anything, is worse than actually having a virus in my opinion), bitdefender (kept popping up false positives, took three hours to scan when other products manage it in half an hour) and worst of all has been the antivirus products included in my local ISP's setup CD's.. It's based off f-secure, so it is actually pretty good at preventing and removing viruses, but everything other than the scanning engine was coded by monkeys, is incredibly bloated and slows everything down
