Sunbelt Personal Firewall. A free Windows firewall. I love the features and interface, despite not knowing it's full security strength. I used it for nearly 10 years on many machines. Unfortunately the company was bought out, no version was ever made that supported 64 bit machines, and now there is a product end-of-life notification.
... fuck MS security essentials...RIP SPF :(
I've always found ZA to be a HUGE bloat. Sunbelt's free for personal use:
http://www.sunbeltsoftware.com/Home-Home-Office/Sunbelt-Personal-Firewall/
"Free & Full Version firewall software for different levels of protection "