
Take a look at Avast as well
We're moving away from Symantec to Avast at work because Symantec is utterly unmanagable on top of not being very good. Avast came out of the pile as the one that ate the least resources, has a decent central management system and picked up most of the current crud. It is free for personal use.
AVG was also a consideration but since v8.0 I've had some serious issues with both free and full flavors. Besides starting to slack on updates, one installation became unbootable following every update (AVG 8.5 Internet Security)