Articles like http://arstechnica.com/security/2015/09/security-wares-like-kaspersky-av-can-make-you-more-vulnerable-to-attacks/ show that security wares themselves exhibit vulnerabilities. That is not surprising, as security ware is non-perfect software after all. The upshot is that security wares that you install in your computer not only increases your security but also increases your vulnerabilities.
There can thus be something like too much security ware, as that would incur too much vulnerabilities. (This issue is different from duplication of AVs and similar misconfigurations)
The subsequent issue then is, what limited number of security wares should you select for maximum protection?
Let's assume prudent computing habits behind a residential router/WAP with strong passwords, i.e. prudent email/browser/Internet habits with the user being reasonably aware of computer/Internet security, however, without the user being a security expert.
In such a 'prudent' scenario: How does a well-selected, well-balanced security software suite look like?