Is the windows firewall sufficient enough protection or am I better off with Nortons etc. ?
Windows SP2 (service pack 2) has a built in firewall, yes, but it does not protect
outbound connections. For example, if there is some sort of "phone home" program that has installed itslef into your computer and tries to transmit information stolen from your PC, the SP2 firewall will not detect that.
IMO, SP2's is better than none. But you're better off installing something more robust, like Zonealarm or Kerio. (both of which ahve free version I believe).