I like all the posts so far. There are some very interesting possibilities.
I think that what we learn of his children with Aviendha is a clue to this perhaps. They are always channeling...always.
That said, here is my stab at this... I think that the deal here is that the Dark One and the Creator are one and the same. I think a clue to that is that the Dark One's power is called the True Power. This is also apparent to me when Rand realizes that life without the Dark One would be just as bad as life with the Dark One.
Others have said it: the pattern is balance. Balance can only come when the objects on either side of the scale are the same. It is the scale that is our problem. It is not really there, but by humanity perceiving its existence it is real and is what enables us to (falsely) see a difference between good and evil.
As has been mentioned the Creator has been absent as a singular consciousness. The Dark One and the Creator are two parts of the same whole (there is all kinds of imagery throughout the series to support this, such as the ancient symbol of the Aes Sedai; the overall undertone and current of the series also fits in with this thought).
You can't have a creator, an Alpha and Omega, and then have a power or force that is beyond his ability to control (by the way, that statement holds true in real life as well; God and the Devil are really just God).
I think that the Rand / Dark One storyline highlights the duality that infects human eyes. After the last battle Rand now realizes that the duality is a lie. It is one, though, that humans can't overcome.
Having touched the threads of creation he has transcended the limitations of normal people and can, because of his experiences and realizations from when he was outside of the pattern, manipulate the very threads of life and creation because he realizes that everything that is and is not are part of the same whole. So he lit that tabac because he now sees that he is the fire and the tabac and Rand and Moridin and the Dark One and the Creator. "He will be one with the land..."