Here's why...
most IT techs and the businesses they work at, run in a Windows limited privileges environment. As long as you keep ALL applications and the OS completely updated religiously(Secunia PSI); and you stick to the NT protections that restricted accounts give you - you can quite literally get away with only running CCleaner - especially, at least before a reboot, log off, or shutdown, so it can clear any malware that may be planning an injection into the startup folder.
I have tested CCleaner in my honey pot lab, and after my various tools detect malware in the temp files, I scan after using CCleaner, and they are all gone! If Microsoft would do a better job building an even more secure environment, AV and AM would probably go the way of the dinosaur. But we all know the crooks will continue to do their homework, and social engineering gets better and better by the day. So I'll always recommend AV and AM solutions, and even others that work completely different, to operate in an infected environment, despite the presence of malware.
