It seems to me that you totally overlooked one of the best free AV products out there - Immunet Protect. I agree that AVG isn't all that great as an AV any more and I'm not really a fan of Avast either - and the free version of these cannot be run in any commercial environment as the free version is strictly licensed for "Home Use Only" (Avast) or "private, non-commercial, single home computer use only" (AVG).

Immunet Protect is free for use on home, non-commercial and commercial computers and there's a Pro subscription available for US$24.95/year. It can also run alongside other AV products and was specifically designed this way.

I do agree with your comments about ComboFix being not for the weak of heart, but I'd also strongly recommend it isn't used by anyone without a good idea of what's actually going on inside a Windows-based computer system as choosing the wrong options inside ComboFix can bring a computer to its knees.

Malwarebytes and Superantispyware are both great tools.