Their is no such thing as a best firewall, reason for this is that if their was a best firewall, no1 would be able to crack it, hack it, it would be liturlty impossible to hack threw, that would be a best firewall, but unfortuniality, their issisnt, what i can do is recommend one to you, its Nortorn Internet 2001 firewall, reason i dident say 2002 or 2003, is because they have alot of problems with windows XP if u use one with their accounts and stuff and sometimes locks you out, most of the time it will freeze on u can crap, but if you update the 2001 to current updates, it will just do the same effect as if it were 2002 or 2003.
also get Norton Anti-virii 2003, thats good and more better, cause it will try and stop most of the common hacks that hackers use like trojans, it would be also wise to get The Cleaner, it cleans and destroys your infected computers that has a trojan.