Honestly you need to consider what you are doing and why anyone would want to compromise your machine in the first place.
Unless you have Mission Critical Items (Or something equivalent) on a WAN Attached system I don't see any reason whatsoever to run multiple A/V Solutions.
Also, like I said earlier, what are you doing on these systems that put you at a high risk? Are you haphazardly clicking around the Internet? Are you hosting information that people would pay big money to get their hands on?
A single quality A/V Solution is plenty for 99.9% of users in the world.
That said, MSE and NOD32, for me, are the only suites that I recommend. Sure, AVG, Avira, and Avast aren't bad (Certainly better than nothing (aka: McAfee)), but MSE and NOD32 are some real quality products.
-GP