Linux is getting just a little more Mainstream.

As I said, I never bother with noise reduction. However, digiKam has a big advantage over the Gimp for heavy processing operations, it supports 16 bit per channel editing. The Gimp is still only 8 bit per channel. It can make a huge difference for things like sharpening. I imagine that the same would be true for denoising.

Looks like the latest digiKam has support for it:

http://forums.dpreview.com/forums/read.asp?forum=1006&message=41994442

In OpenSuse the current version of digiKam (using Tumbleweed repos) is 2.6.0. But, 2.7.0 must surely be right around the corner.