I've been using ZoneAlarm for quite some time now and have grown sick of it as it sucks up my resources like mad, often making it so that I can't even watch a video without it lagging or something once very half hour or so, regardless of the fact that I'm not actively using the internet. Apparently it's something to do with the vsmon.exe file and I've searched for that around the web and the fixes are generally non-existant (eg. "try reinstalling" or "get the paid version").

Can anyone give me some good examples of decent firewalls? Preferrably freeware, obviously. Please do not mention "Linux" or "reinstall Windows".