A few reasons:
- I don't believe the small extra resolution is worth the extra time required to deal with moire. I know that I will not have the time to scan images for moire and will end up finding it after printing large images which will generate a significant cost,
- Since I intend to keep stitching anyway, this extra detail is even more irrelevant,
- The difference of price in Japan is nearly 600 US$ which corresponds to the money I just spent on a Sigma 8mm circular fisheye which I find to be much better value,
- I still have philosophical doubts about the relevance of capturing images that can mathematically not be a faithful reproduction of the scene due to the presence of false colors and false details,
- I intend to use the D800 for video also and there are widespread concerns about video on AA filter less devices (unconfirmed so far though),
- For family reasons, I need this camera quickly and the 3 weeks early shipment of the D800 will actually make a difference for me,
- Finally I know from my D3x experience that proper sharpening manages to remove most of the initial softness one can feel when opening images in a suitable raw converter,
We may find out that Nikon did an outstanding job with moire control on the D800E and that there really are no issues with moire. Worth case I'll get one in a few months as a back up.

Thanks for sharing your reasons.
I am quite tempted to get the E version. I think I will wait to see more samples. Hopefully LR and other tools will get support for D800(E) soon after the cameras start shipping.
My thoughts are:
- one cannot get rid of a moire even with the AA filter anyway. See current Lloyd's blog for example, the D3x test pictures with the roofs have a lot of it. The bad thing about moire is, that once you start looking for it, you find it more easily :-)
- I am not sure about the false details, are the blurred details more real than the aliased ones? Probably not, sometimes maybe better looking and sometimes not. Deconvolution is great, but has trouble with noise and cannot reconstruct the signal completely. It might introduce slight halos as well
- I will be (probably) not doing any wedding or studio work with clothes, so the risk of loosing critical shot because of moire is quite low
- don't hear much complaining from MFDB users about moire
- OTOH the price difference is indeed not negligible, nearly 20% here as well right now
It is a bit difficult to choose, but having the choice is great and I am happy Nikon offers both versions ;-) I would prefer to have the E version without any low pass filter though.