Wow, there's a lot of experience on these boards! A good bit of overlap, but also a good amount of diversity.

Unfortunately my time is more limited than in my hs and college days, so I fear I can't take a look at all these systems you guys recommend.

What I find, though, is that a lot of ideas from other systems can be adapted across systems. In any case, you can usually learn from other systems.

I have been working on a BR conversion for a while now, with a few goals in mind:
1. Improving the simulationist aspect;
2. Streamlining gameplay, particularly for PBEMs;
3. Scalability (traditional domain level to intra-domain, or up to faction and nation level--so 3-5 players could easily play out the drama of Anuire, or the five tribal regions could be played); and
4. World-building and world-running mechanics adaptable to any D&D setting as a DM aid.

It'll be 4e compatible and take some cues from that, but I'm not focusing much on the adventure level, so 3.5e v. 4e won't matter that much. I'm getting close to having a reviewable outline of the mechanics (without much flavor explanation, yet). I'd like to benefit from your collective experience and critique, however, so I'll put it up when I have it ready.

Aside from that, though, from what I've hearing, some of the best systems you guys have put forward are:
1. James Bond RPG
2. Earthdawn (for magic)
3. Paradox
4. Machiavelli

I don't have experience with any of those. The Areas of Knowledge are a case of convergent evolution--I was recently applying a similar concept as an extension of the Character Backgrounds mentioned on another thread here. It's helpful to hear about how they worked in the Bond system. Any other winning ideas worthy of brief explanation from these systems?

As for systems we'd like to promote the most, I'll plug Eden Studios' Witchcraft & Armageddon (the Unisystem), since no one else here seems to have seen it yet. My brother loves Engle (a German product).