This makes a good point - there is a great risk that having installed asn AV product, the user can sit back and relax, thinking his system is safe - camplacency sets in.
An informed user is the best defence, and the better informed the user, the better the protection for the situation. Computer security is a process, not a product! (To loosely quote Bruce Schneier)
In any situation, the sysadmin should conducyt a 5risk assessment to see what the likely attack scenario is, and what steps need to be taken to mitigate them. In a corportae environment this will include acceptable use policies, together with some technical measures.
In a home environment, where the roles of system admin and the end user are the same persojn, the risk assessment will be less formal (probably coming down to "I'd better install some AV" - which one is best?) but really it should be a bit more than this.
Mitigation measures should include considering the operating system vulnerbailities, considering firewall protection for direct attacks by otheer malware, not routinely running with admin privileges, being circumspect about opening unknown e mails, and being wary about following links in e mails, and avoiding warez sites and the like. AV should then be considered as backstop, to kick in when the previous measures have failed.