On my wifes PC I have installed AVG as I much prefer ir to Avast!, it works fine.
I suppose it depends how much risk you put your PC at. My wifes PC is put at much lower risk than mine so it uses a free AV. I pay for the AV on my PC as it more likely to come in to contact with the worst the net can throw at it.
But I wouldn't use Norton, and I certainly wouldn't use McAfee as it is so bloody intrusive.