I think it's a very smart approach to do a real in-depth assessment, before spending thousands and thousands of dollars worth of camera bodies.
More pixels offer some opportunities and some drawbacks all at the same time. What value to attach to that is entirely personal.
I've always lusted after a FF 6MP camera, using modern sensor technology and super-sized photosites. Sadly it doesn't exist because of the often mindless race for higher pixels.
But there is more to the equation than pixels. The modern sensors encompass a much wider dynamic range than the 4-6 MP cameras of old.
Is the D2H still "competitive" ? Heck yeah! - in the rights hands, it is.
It has all the conveniences of a top-end camera with external control, fast everything, near-bullet proof chassis etc. etc. And, it's also now very inexpensive. Practical ISO range may be less than the top-end cams of today, but for the difference you can buy a lot of quality glass and a couple of strobes to go with it.
When you stop thinking of the body alone, but look at what you can get as a system for a fixed budget, it is very likely that you will have more versatility by spending less money on an older body and buying other stuff to go with it. And you can still upgrade as often as everyone else...just some years later. Soon the D2 and D2X will cost the same as the D2H and 5 years from now, the D3 will be just as dirt-cheap.
And if you really NEED to have high pixel count, buy an F5 or F6 and a quality slide scanner and blow everyone away. you can still use all the same quality glass and lighting options from your D2H.
From a very pragmatic point of view, I think that my older D40 takes better images (in my hands) than my newer D300. I stick with the D300 for "serious" stuff due to the convenience and I am seriously thinking about getting a D2X.
Show some more of those great D2H images, will ya ?