I have also dumped Norton and after several trials I selected Avast!. I have been pleased with the protection I get. My computer is used by several teens and I see the results of Avast's protection every time I view the logs.
In this case, free is good enough. I also recommend that you periodically use an on-line virus scan because it is fact that no one anti-virus program can offer 100% protection. Feel free to use any one of the links in my signature if you don't have a favorite.