At the time I was running OSS the only other firewall with almost as fine grain control was Comodo Internet Security Suite - I have no idea if that is still the case though.
I've never heard a lot about Comodo's security suite. The extent of my knowledge was that it was the only firewall (other than Agnitum's) that will pass 100% of leak tests. I decided to poke around it a bit this morning & the results surprised me. I knew they had a paid tier and a free tier. I figured it was like all the other security software publishers in that the free tier was a stripped down or limited version of the paid product.
No, it's not. Turns out the free version is the full-on complete product and not limited in any way. The paid version just gets you tech support and expert-assisted virus/malware removal. Comodo's trying to build up its brand name and reputation in the security community (and sale SSL certificates) so part of their strategy is giving a complete security suite for free.
I've installed it and wow, it's comprehensive. I don't necessarily mean that in a good way, either. There are settings to alter nearly every single way the suite behaves. If someone doesn't know what they are doing they'll leave their system completely exposed while mistakenly thinking that their system is protected. What's worse is that the default settings are a balance of "totally locked down" and "not bothered by prompts" that I would not have necessarily have chosen as it's a little too lax, IMHO.
I'm going to give it a go for a few days, but I'm a computer security geek & playing with stuff like this gives me great joy, but before anyone else decides to install this, please keep in mind that this thing has a 648 page PDF manual. That's six hundred forty-eight pages. Get too overzealous & strict with your settings and your PC is not going to boot.
If you want to get an education (or already have one) this might be a fun ride, but for the Click Next-Next-Next-Done crowd it will mostly end in salty tears.
It's too bad that these Internet Security Suites don't allow you to uninstall parts you don't require or at least stop them from using resources, you could continue to use just the firewall component then.
I will give the Comodo guys credit for their installer. They list the different modules: AV, firewall, hardened browser, and their GeekBuddy expert service. One can pick and choose what to install and what to leave out. I went with just the AV and firewall. It's going to take some serious fiddling around to decide if the suite is worth keeping or not, though.
If this doesn't pan out I think I'm going to try 4wd's solution of MBAM and WFC.