IMHO, AVG is every bit as good, even better, than Symantec. And AVG runs very light and does not load down your system as much as Symantec.
Just remember to keep the virus definition database updated on a regular basis. I update every Fri evening, for sure, and usually at least one more time sometime during the week.
What are you running for a firewall?
What is a firewall? :)
I have nothing at home. Know of a good free one?