You must try Topaz Denoise! After being told by so many so often, I have. On a free trial. Which proved trickier to set up, as these things too often are.
Anyway. The results? Noisy shots. Noise gone. Great. But good shots without noise don't become great. The Topaz sharpening tools don't work any magic. (Watermark part of free trial)
Forced to use high ISOs? Topaz does trick. Looking for magic on already good shots? Dream on!