Neither.
McAfee doesn't have a firewall for Mac OS X and you can't easily buy their Virex anti-virus software.
Norton products tend to cause more problems than they solve.
There is a built-in firewall under Sharing preferences.
You might consider Intego since they have a whole line of stable products and aren't Norton. They have a very good firewall with domain filtering along with anti-virus software. Their customer service is not so good--maybe because they're in France.