It all depends on what works best for you. Many people, including myself, use Avast and it works just fine. However, you may find that Bitdefender or Kaspersky works better in your system.
Even with a good anitvirus, I still HIGHLY recommend you have a secondary opinion scanner such as Hitman Pro, Malwarebytes or Zemana Anti-Malware. They are all free, but do have their limitations to the paid versions.
Of course, common sense it the best anitvirus.