oxiclean said:
either NOD32 or kaspersky (what i use). they are both really great, and kaspersky updates its database every hour, in addition to being unintrusive.
ditto i love either one of these programs kas tends to be more resource intensive than nod but kas is also imo better than nod, kas will elimiate threats in real time or stop them outright before they can even do anything. I also like security suits form nod and kaspersky they have good firewalls and anti spam, spyware utilities.
Microsoft security essentials gets very good marks and is free with windows 7, but the default windows firewall is full of fail and MSE does nothing with the built in windows firewall.
Panda and avg get good marks for being free, but having use avg years ago for a bit it did not take me long to find a way to infect my system
, went with KAS and not had any way to get around its defenses. Course this was years ago avg and such might be much improved over my experiences and tests on them since then.
But if you go with a pure av solution look into augmenting the default windows firewall, comodo is an excellent firewall and passes all firewall tests with flying colors but it is not noobie friendly you need to have some idea what your doing to work with it and get max protection.