mchain
8
Actually, what can be more important than the choice of an a/v is the proper set-up of user accounts.
Guest account for the kids, standard for teenagers and non-admins, and admin only for the one responsible for maintaining the system. Also a good idea to set up another admin account to use for reserve in case the main admin account profile become corrupted and not usable. That way, if any account becomes unusable a new account can be created for that user, and all data moved over to the new one, and the corrupt account can then be deleted.
Restricting user rights will go a long way in preventing malware infections, and if one does occur, it will be limited to that account.
Always save old program installation files in Downloads and elsewhere; avast! is a good example of that.
Plus, do not share the admin password with anyone.