[citation][nom]alidan[/nom]i have to agree with you, not on the camers company, but on the rather have D800... well really i would rather have the 5000$ version they make but i cant remember its name... there is a certain point where more quality is really just lost... there are very few cases that call for a 10k+ camera, even in the professional realm. and at some point, no one will see higher quality.[/citation]
Are you referring to the D4? The image quality of the D800 is about 10% better and generally it's the better camera for most purposes, the D4 is more expensive because it's specialized for low light photography with insanely high ISO.
There is not really a certain point where quality is lost, remember a big advantage of high resolution cameras is that you can crop from a larger image to create a different composition and still have enough detail to make a big print.
Leica cameras are not any better than the products offered by Canon, Nikon, Pentax, or the others. They just cost a lot more.
The DX0Mark image quality score for the Leica M9, their top of the line mirrorless DSLR, is 69. That is a middle of the pack score at best, barely beating some $500 cameras from other brands. Every other DSLR manufacturer offers better image quality for a fraction of that price.
For comparison, here are some image quality scores from other brands. I should point out that I am only comparing mirrorless DSLRs (like the M9), so this is an apples-to-apples comparison.
Sony NEX-7 -- 81, SLT-a77 -- 78, NEX-5N -- 77, NEX C3 -- 73,
Pentax K-01 -- 79
Leica M9 -- 69
Panasonic Lumix DMC-GH1 - 64
Samsung NX11 -- 63
While the M9 is better than some of them, you'll notice it is nowhere near the best, yet it is by far the most expensive, at 10 times the average price of the others listed.