On my PC I use the ESOT NOD32 Internet Security suite. On my Mac I just use Little Snitch to monitor network connections, without an anti-virus program.
If you have any bank account in HSBC, LLoyds or Barclay they give you registered antivirus for free... and all the updates will be authentic.
I used to use avg and and then I used avast for awhile I used like pc doctor or something, but now I just used malwarebytes
I would like to suggest a combi of Avira AV and Comodo firewall. This is the best ever I've tested. It usually helps you in getting up the things in a proper manner.
AVG Internet Security + PC Tuneup in conjunction with Ccleaner = fighting to keep my computer clean and virus clear