I have found Norton and McAfee to be EXTREMELY over-rated- and I'm being very polite here. Computer Associate's E-Z is, in my opinion, the best of the commercial junk.
Luckily, I have a brother who's software company is used by the international community and their governments.
The answer to your question is that mine is a custom job. Between that, and only using dial-up on my business computer ( which I unplug after every session), my business computer(s) have ALWAYS been virus free.
The "fun" computer ( DSL, wireless) has been hit, but not since installing big brother's software.