Topaz DeNoise on sale for half price ($40) until April
I am fairly ambivalent about noise reduction software, since I very rarely feel that the ends justify the means, and it's way too easy to end up with a plastic-looking artifact-ridden mess that doesn't have any of the pleasing texture of "natural" noise. However, I did try the free trial of Topaz DeNoise, and found that it's better than any JPEG engine I've found, or than Lightroom's noise-reduction / sharpening options. I haven't compared it with any other dedicated NR software, but the consensus is that it's one of the best.
It's on sale for $40 until the end of March. This seems like a pretty good price to me...I've sold a few of my cheap lenses, coincidentally, for $40 a piece, so I'm considering just grabbing it. I feel like it will probably extend my "worst case scenario" shooting options, given that my GX1 is not really comparable to most modern APS-C sensors once the ISO heads north of 1600.