I'm very happy with ESET NOD32

relatively cheap for a 3 year license. very small footprint. works (as far as i can tell). you can customize it relatively well (eg to don't meddle with your browser and try to "help" you by blocking sites). it's also built with some concern for gamers i hear (if you care about that - i don't).

when i started using it two years ago i was looking for something that had good reviews (which NOD32 definitely has). i also wanted an independent manufacturer. ideally from the EU, since both US and Russian intelligence are known to meddle.

free av... i'm more of the school of thought: you get what you pay for. and if you don't pay anything for a product - *you're* the product. but that might just be me...