My answer to you would always be yes because they are a helpful tool and most of the time catch intruders. Though at times they can slip by but better to have at least something. Then there's other people like a friend of mine who refuse to use it and say they are tech enough and when they catch something they go through the registry manually and do all the dirty work on their own. I wouldn't suggest that route though because i'm sure he has something possibly lurking anyways and says he used malwarebytes just to check it once and says it's fine
. Anyways it's your choice but the other route without a anti virus is going to be a bit bumpier and I wouldn't recommend not having one. Any good free alternatives if short on cash are better then nothing, I use comodo anti virus internet security premium and it comes with a real good firewall and use their free version since I feel it is sufficient for my needs at the moment.
Anyways this is my recommendation, really good anti virus/firewall combo. If you decide to use it I suggest after install to uninstall geek buddy and the comodo browser which are not needed.
Link is in blue below. http://www.comodo.com/home/internet-...t-security.php