OK it really depends on your access method, ie via router with its own firewall or just an adsl modem.
Eset is quite good www.eset.com/ and its product ESET Smart Security Home Edition which then covers you for AV as well.
Alternatively you could use the ms vista firewall and eset nod32 as an AV client. People may well scoff but if you have a hardware firewall gateway e.g. draytek adsl modem then your very well protected.