If you want to protect yourself against Viruses get a real Anti-Virus program such as NOD32 or Kaspersky.
I do like to push free software myself... but in the case of anti-virus I cannot recommend any of them. They all have their pros and cons... but in the end all of them fall short of the comprehensive protection you need from a proper anti-virus program.
If you are OK with bare minimum support though, then I suppose one is as good as another.
Most guys on this board use AVG, AVAST, BitDefender Free, AVIRA, etc. Just pick one. If you like the colors or the interface. Won't make much difference in the end.
BitDefender can update using local only bandwidth so that's a good reason.