In a PM just now, an AP member asked me for some tips on using Neat Image. I thought it would make more sense to post the answer here so that everyone can read it, and other members can add their own tips and tricks. I am not by any means an expert at using Neat Image, nor at post-processing more generally, but I've been using it for quite a while and have developed some methods that work fairly well.
For wildlife work with long , you nearly always wind up using a higher than you would ideally want. Most experienced bird photgraphers routinely work at 400 and will readily go to 800 if needed, and then, depending on the camera model and the circumstances, higher again if they have to. Most of my 1D III shots are at 500 or 640; 400 if I can, 1600 more often than I like, 3200 if I'm desperate. On any camera, the luxury of shooting at 200 is a rare one.
Noise reduction should be regarded as an integral part of the photographic process, certainly once you go past 200. Think of running Neat Image the same way you think of cropping, adjusting levels, , and so on - it's just part of what you do with every image. I believe it is much better to turn all in-camera noise reduction OFF - your computer is vastly more powerful than any camera logic, can run much more sophisticated software, and above all, can do it in different ways for different images - this puts you in charge and let's you process each image in the best way rather than be stuck with the irreversable one-size-fits-all of in-camera noise reduction.