@_@'s accessment should be in the right ballpark: 2-3 stops as fast as D200. According to Nikon, D3's high ISO noise is comparable to that of Canon 1D Mk III, which is about 2-3 stops as good as D200 or the D2(s?).
The best high ISO noise camera in this generation should be the 5D Mk II: unlike the 1D Mk III (1.3x crop), it is a full frame camera, which means it collects 70% more light. Which means at ISO 10000, its noise should be comparable to 6400 for 1D Mk III or D3.
The current 1Ds Mk III should also be extremely good at high ISO: although the noise per pixel will not be as good as that from 5D Mk II, but when printing out, it should be about the same as 5D Mk II.
The best high ISO noise camera in this generation should be the 5D Mk II: unlike the 1D Mk III (1.3x crop), it is a full frame camera, which means it collects 70% more light. Which means at ISO 10000, its noise should be comparable to 6400 for 1D Mk III or D3.
The current 1Ds Mk III should also be extremely good at high ISO: although the noise per pixel will not be as good as that from 5D Mk II, but when printing out, it should be about the same as 5D Mk II.