actually the best defense is knowing what you are doing to begin with
Teaching yourself to not auto open emails with attachments...not to auto accept downloads ...etc...etc...etc. is the best protection that you can have...the rest is kind of supplemental.

Norton (in my opinion) is junk to begin with...as soon as you don't pay them your system is auto flooded with all kinds of crap....not to mention all the known issues Norton has caused with computers that it is installed on.