[Butter]

My 2 cents:

I love Mind Mapping. Currently using the free XMind.
Seems to be a great mapping tool.

However, it would be great if Omni would have the option for exporting (or importing), data for mapping programs.

I don't think it would be a good idea to have mapping on a program like OmniFocus, but it would make sense on OmniPlan.

In the meantime, I find Mind Mapping an essential part of my process.
My method isn't entirely David Allen in the pure sense of GTD. I utilize parts of GTD on a daily basis, but I also use, Anthony Robbins RPM method which I personally find works better for me on a ultimate outcome, different level. GTD works for me on a daily task level.

Mind Mapping can work with GTD and Omni, but it doesn't need to be integrated per se. It would be nice if it could export and import at the least.

Another poster mentioned DevonTHINK, and I have to agree, that this is an amazing piece of software to utilize reference material and organize information. It also works with both GTD and RPM methods.