buy a mac, that way you don't need any virus protection! Just kiddin, I am a mac owner, but also a fan of windows...
Thing I think is that when you're offered something as part of say, a broadband package, they are just trying to make money. They don't give a dam if you're protected or not, they are just in it for the money, so as a rule of thumb never take them up on their offer.
AVG is a great little peace of kit, and as mentioned above in the other posts, when used with other products such as zonealarm, you can't go wrong. I paid for zone alarm and virus scanner (which i think is powered by avg but may be wrong) for like �20 if that, and never looked back since.