My Own Multigenre Post-Apocalyptic Setting

After much thought and deliberation, I've decided not to do a Rifts D20 conversion at all. Instead, I'm going to create my own multigenre setting for D20 Modern. I may still use Rifts for a bit of inspiration, but that will be the end of it.

Ideas that I would like to incorporate into the setting:

• Two powerful organizations locked in a cold war, one that stresses the "purity of humanity" and the other that embraces the supernatural (similar to the Coalition vs. Tolkeen conflict of Rifts, but a much more prolonged stalemate).
• Ghouls and Mutants as demihuman races (similar to Fallout)
• Walled (maybe domed?) cities surrounded by lots of unclaimed wilderness (like what you see in the aerial shots of Bregna in Æon Flux)

Ideas that I would like to avoid:

• Cheezy interpretations of literature and/or mythology (such as Merlin/Mrrlyn in Rifts England)
• Giving a specific reason for the apocalypse... perhaps different groups tell different stories, but the truth is only known to a select few (or nobody at all)
• Making any organization or race unrealistically good or evil... I want there to be a lot of gray areas and moral decisions in this campaign... questions like "which one really is the good guy?" should be common
  

I may add more to these as I continue to develop the setting, but I want these to be my guiding principles. Now, I just need a name. I briefly considered Nexus, but it appears that another blogger is already working on a multigenre setting by that name. Frankly, I'm stumped... and open to suggestions. Perhaps something like Sundered Earth?