I'd say it's more your lens than the camera that's hurting your shot. I took this with the D70 and the 18-70 (iirc... might have been the 70-210 f/4-5.6) at 1600 ISO. I also forgot that I had turned the ISO up from the previous day's shooting. Yes, Neat Image makes the images overly smooth (I usually just do "remove half of the noise"), but a quick Unsharp Mask helps bring back the sharpness to something more normal.
D70, ISO 1600, Neat Image ('default' image cleaning), Unsharp mask:
I took a bunch of photos that day all with the same 'problem' and solutions (see gallery for a larger version of the above image as well):
http://www.fakelag.net/gallery/v/nor...ghlightId=4574
I've actually been rather impressed with the high ISO performance of the D70 since I was expecting it to be unusable as so many people suggest online. In actuality the noise that exists is nice and clean and easily fixable. My cleaned up ISO 1600 images look only slightly 'worse' than my untouched ISO 200 images. It's one more step.. but not a real problem.
Good luck!