Ive used Helicon a few times lately, it works nice but it does make the image soft, so what I did was clean an image up, save it as a bmp, put it in the original file as a layer, and masked out the areas that I want sharper detail on.
I use the noise reduction built into BreezeBrowser for my 10D. I haven't had to go beyond that. I don't know how it campares to other software, though.
Somebody has made a set of free photoshop actions that reduce noise in digital images. They work fairly well for me, but not perfectly. They're good if you don't want to pay anything (apart from Photoshop). You can get them here: