I've been using ClamAV / ClamWin for several years.
It was primarily design for scanning email attachments, but the client is OK for usage on your desktop. Also, it only detects threats but doesn't clean the infected files - which is OK, because you shouldn't trust AV software to clean your files. Once your computer is compromised, you're better off formatting your hard-drive and reinstalling everything from scratch (which is why it's always a good idea to have periodic backups of your work).
It was primarily design for scanning email attachments, but the client is OK for usage on your desktop. Also, it only detects threats but doesn't clean the infected files - which is OK, because you shouldn't trust AV software to clean your files. Once your computer is compromised, you're better off formatting your hard-drive and reinstalling everything from scratch (which is why it's always a good idea to have periodic backups of your work).