Woudn't bother with half of the stuff listed here, most AV has it's own AV database and all differ. None is 100% effective, would never ever pay for AV complete waste of money but I recomend free.
With a non free AV you wouldn't suffer from a virus that survives a format. And I'm not worrying at all about malware that break my system. I worry about malware that actually work seamlessly with my OS, and free AV doesn't do anywhere near as good on protecting from that stuff as a commercial product does.
5 Years I tried every type of AV out there including all the above listed, all a waste especially those that cost money, Norton + just hog memory and waste space.
When did you try norton last time? It has used less resources than AVG the last 3 years...
I fixed my PC myself countless times and have formated over 12 (just to remove the 1 virus that no AV could catch), have had a virus that persisted through a format that I had to fix manulay. Finally, last 2 years I stuck with a few free AV and have not had 1 virus since.
Interesting. I've run commercial AV-suites the last 7 or so years, and have formatted 3 times, not a single one was because of a virus. I wonder what that could mean...
AVG Free
AVG is a false positive machine. It consistently alerts on things that's not viruses. It also slows down the machine way more than other available free software. Of all free AV-software AVG is the one I recommend the least. Avira or Avast is the way to go if you can't afford a real suite (Personally, I recommend Norton IS 2009, it's for AV-suites what Windows 7 is to Vista... Yes, REALLY).
Chance is if this setup won't catch your virus/spyware ask on tech forums (there are many out there) or learn to remove it yourself.
If you learn your hijackthis list of by heart you can spot any new infiltration that appears, if not there are more hardcore spyware removal systems out there that require safe mode and wipe sections of your pc.
But you should always have AV installed, free stuff listed is the best.
You assume that all malware will cause a noticable degradation of your system, which is not true. With your software setup, and naive attitude, your computer could be part of a botnet without you knowing it.