Is it neccessary to purchase anti virus software or will free stuff be enough?

[8shaky1]

I've just purchased my first gaming pc and it's on it's way now. I was wondering whether I would need to purchase some anti virus for it and if so which one would you reccomend? Or would you suggest some of the free anti virus software out there at the moment?

Any help is much appreciated.

 

[Onus]

I have used both pay and free software. I've not noticed any remarkable difference; I don't recall my last infection.
Oh...I've used both AVG's and Avast's free versions. One of my ISPs provides Norton (though I may be about to ditch that ISP).

 

[8shaky1]

I have used both pay and free software. I've not noticed any remarkable difference; I don't recall my last infection.

Ok thanks for the help, is there any particular free software you would reccomend?

 

[Onus]

I edited my post to add it. I also use MalwareBytes in addition to whichever virus scanner I'm using (AVG on Gypsy and Midget, Norton on Phoenix and Omega).