First of all, never take advice like "I use this-that and am OK, so it must be OK".
Includes me: I use the big two free ones and I've never had problems.

Seriously, up to about a year ago, AVG and Avast had the best reviews in terms of finding the new virii first, before the others. Haven't gone around the reviews lately, but I put my money on them anytime, given they're also free.
Most of the people I know that do heavy, careless surfing use those two - never Norton nor McAfee.