Avast! Free Antivirus 6 is my first AV and i am still using Avast!
Loved Panda's Web AV scanner, when it was free. Made some good money fixing PC infectionsWhen we bought our first computer in the family back in 2001, there was Norton AV installed on it. After two years, I switched to AVG free. In 2007, I used panda AV for about 5 years, then Avast for some months, Panda again and then Norton 360 till now.