>>2
Double LOL. Hope you have a Plan B.
AVG, Avast, F-Secure, NOD32, Kapersky, etc.
Just avoid Norton/Symantec, McAfee, and MS OneCare or whatever and you'll be okay. Look at the Wikipedia list of AVs, and pick one based on price, record, features, etc.
My personal favorite is an OS that doesn't suck, with OpenAV and ClamAV so I don't accidentally help spread shit to other people.