Well, in my personal expirience (sp), Windows Firewall has done great, it blocks all bad incoming connections. All my friends know how to "hack" computers, and yet I give them my IP and have never been "hacked" by them. ZoneAlarm on the other hand, gave me problems, not with incoming connections though. The problems I had with ZoneAlarm were mainly with programs. It blocked the ones I didn't want blocked and it didn't block the ones I wanted blocked. Even though, I just went to the settings and changed all of them, it was still a big hassle. All in all, you can get ZoneAlarm, but if you don't need "added" security just stay with Windows Firewall.