Hi, A couple of points to share.
I'd recommend AVG, but the choice is yours. Actually I've paid for AV in the past and if I were to pay again I think I'd go back to Panda before Norton (Symantec).,having used both.
The NAV that you are getting is a trial,then you need to subscribe. You may know this,but want to be sure.
Take a read at these posts,it may help with the final decision.http://www.bleepingcomputer.com/forums/t/34671/how-to-remove-your-norton-products/
And just to be sure again. Use only 1 firewall ,1 AV and several spyware apps. Which of these are you using now?
Another note,install AVG before uninstalling NAV,if this is the situation.