Hey Mongo, I was adding my other reply as you added yours.
For (predominantly) shooting birds I wouldn't choose the E model.
The lower specced low pass filter will most likely cause moire effects in the high frequency patterns in the birds feathers.
Where there is high frequency repeating patterns, such as many fabrics, or distant building textures, or birds feathers, you risk getting moire patterns.
You can get software that reduces the effect, but this is not the same as not getting the effect in the file in the first place.
It(the software) reduces the resolution of the fine detail anyhow, so why bother trying to get it in the first place.
There are particularly good reasons to have the E model, and because I primarily concentrate on this genre, Landscaping comes to mind as a reason to get the E model.
It's very rare to get repeating high frequency details in nature like that.
I've been reading that a lot of folks (on other fora) are interested in an E model for Macro, where you'd expect the extra detail level to be an advantage, but again, in many macro situations you get very fine repeating patterns that will cause moire ..... think of a fly's eyes or very fine hair like structures in a flower.
I hate moire, and while this was a long time ago that I had to deal with it, and software may have come a long way since then, this was with the D70s.
A camera notorious for producing moire whenever it could!
Strange little fact about this camera, is that it used the sensor from the D100, which was less susceptible to moire, I suspect in an attempt from Nikon to get better details. But on the D70/D70s, it kind of backfired. The D70 models obviously had weaker AA filters than the D100 had.
But it was well known too that the D100 image could be brought back up to the same level of detail as an image from the D70's could be got!
USM! Appropriate use of USM got images back up to similar standards of detail to the D70 cameras.
It seemed that Nikon relented with that sensor's AA filter, because they also used it in the D50 and then D40 cameras, but they never had moire issues like the D70s did.
It is true tho that in some cases you will get detail in the image from an E model that you may never get from the non E model, as you would expect from a lower strength AA filter on the same sensor, but you risk seeing this moire issue as well.
There is a great example of the issue on the Nikon site:
http://www.nikonusa.com/Learn-And-Ex...slr-tech-moire
While it's great that you can ultimately get more detail from the E, look at the last image to see the moire patterning.
One thing tho, and that is that even tho the fabric in the kimono did produce moire patterns in the image from the D800E and not the D800, if you look at the sample images from the D800E on the Nikon site, the fabric in the kimono doesn't produce moire colour. So the image can be captured(or processed) to eliminate the issue .. just something to be aware of.