j0 all,
I've been using Agnitum's Outpost for a few months now (before that, I was using ZA).
It's true that ZA has become overbloated and they also didn't want to listen to users' suggestions on improving the product. Result? Nobody wants to use it anymore.
Anyway, around this time, Outpost is the best personal firewall because of its configurability and flexibility. It allows the users to create specific rules (e.g. "don't let Internet Explorer connect to www.sex.com" etc.) and has plugin capability - current ones are able to filter out ads and active content (ActiveX and stuff).
You DO need to know how internet protocol works, at least in the abstract way. Otherwise, let your geeky friend configure the firewall for you and (possibly) you will be asked questions from time to time whether you want a certain application to access a certain website, which is a great weapon against some spyware programs.
The free version is missing some minor (well, minor for average computer user) features, like multiple configurations and password protection... they have a comparison chart on their site somewhere.
As for the new version, 2.0, it has yet to come out as a beta... It's been in the works for a long time but nothing has become public yet
Be aware that from v2, registration will be required for the free version (it's not required right now)
hope this helps
cheers,
Fry-kun