I have been quite happy to trust the built in XP Firewall and not use ZA or Norton as I have been to the Gibson site many times to do the tests and all my ports are at Stealth.

But fellow networking students tell me I should use another firewall as the XP one is not aggressive enough.

Are the Gibson ShieldsUp tests really conclusive and am I really safe with the XP Firewall? If not, should I use ZoneAlarm or Norton, I am comfortable using either.