What's a good free antivirus?

Im getting sick of paying upwards of $50 canadian a year to use norton internet security. Are there any good free antivirus programs that have most of the same functions. Also keep in mind that I dont need a firewall because I will be using the one that comes built in with windows. Thanks for the help!

-Edit- I looked at the thread a bit below and realized my thread was useless...sorry for posting something that was already posted. i got all the info that i needed. Mods go ahead and delete this post if you want.

You should try Avast! Home Edition.

Avast or AVG are both good free AV solutions.

As for the firewall, I'd still get something other than the Windows Firewall. AFAIK, Windows Firewall doesn't protect outbound, so if something's on your comp and it's calling home, you won't know. Either Agnitum Outpost (http://www.agnitum.com/download/) or Sygate Personal Firewall (http://smb.sygate.com/download_buy.htm) are free and work well.