Hi,
It's quite impressive what you do to keep your computer free of viruses and malicious software.
But, have you thought of the possibility that one day your computer does get infected with something and maybe even crashes? Have you thought about backing up your HD or some individual files occassionally? This way you can be absolutely sure that whatever happends you can restore everything the way it was.
I would recomend you Acronis True Image http://www.acronis.com/homecomputing/products/trueimage/ , i use it myself and it did actually save my PC once after a complete system crash (i don't use so much preventive software as you - maybe that's the reason something got to my PC).
I did change my antivirus after this incident and since then nothing happened, but i still backup regularly just in case and recomend everyone to do so.