i am currently using Norton System Work which is no longer being renewed.

i am currently using Norton System Work which is no longer being renewed. I am also running the free Zone Alarm. What would you suggest I use to replace the Norton? They are suggesting Norton 360 version 3.0 or Norton Internet Security 2010. Is there a free version of something that will work as well? The more I read about them the more confused I get.
Thanks Dave B.