This poll is pointless, as it doesn't provide an objective basis for selecting an A-V. It's a popularity contest, which proves little, IMHO. Better to look at AV-comparatives.org test results over a number of years. They user rigorous procedures which they explain, and provide a basis for an objective comparision. Go to...
---> xxx.av-comparatives.org/comparativesreviews/main-tests
(replace xxx with www) and click on the "On-demand comparative" link for latest results. For a multi-year comparison of the main A-V players, go to...
---> xxx.av-comparatives.org/comparativesreviews/main-tests/summary-reports
and click on the latest summary report, which provides an aggregated comparison and a nomination of the best for each year.
They are now penalizing products that have a high false-positive rate, so AntiVir is rated lower than it used to be. I still find it the best value of those that are top-tier products. As they say, an A-V program could have a 100% detection rate by saying everything is a virus. NOD32, Kaspersky and Symantec are also superior.
With their 2009 products, Symantec has fixed their resource-hogging ways and their products are now supper fast, yet also have among the highest detection rates and lowest false-positive rates. They are still too expensive, IMHO, but are great at transparency and effectiveness -- customers can install them and forget them, and still be well protected. Honestly, it's a toss-up between NOD32, Kaspersky and Symantec for "paid-for" A-V programs, in my view. For freeware (non-commercial-use) versions, AntiVir, Avast! and AVG would be my choices, in that order.
Cheers.