I have a few Operating systems
I don't recommend using more than one AV on any system, unless you use one for background scanning
I use one of all the following
AVG
AVAST
AntiVir
BitDefender
I like all, depending on what the users experience is, depends on what AV to get
For ease of use>>AVG
For something similiar to Nortons>>I guess I would say AVAST>>(Edit)Not GUI, but scanners incorporated
AntiVir>>Very good reputation, most users don't know this
BitDefender>>No realtime protection with the free version, keep this in mind, but a very good scanner