I've been running Gentoo for the last 10 years at least.
I've got DPP working under Wine, it's not perfect but it gets the job done. I shoot RAW and then use it to batch-convert to jpeg, I use Gwenview to view all the jpegs and pick the keepers.
Then for the 1 in 100 special shots, I got back to DPP and maybe give it the occasional highlight/shadow/contrast sliders and noise reduction.
Then I use GIMP to edit the jpeg, but not much. Normally just crop and resize.
ps, DO NOT judge GIMP by trying the windows version. I've tried it and it is one of the most horribly annoying interfaces ever. GIMP on linux is a pleasure to use. Don't ask me why they're different but they are.
I've just recently had to install a Vista virtual machine using Virtualbox though, to be able to use my new Epson R3000 printer to its potential (I know you can print from linux but I've never tried). I also run Silverfast AI on it for my Epson v750 film scanner (I've been scanning in linux for a year but silverfast is so much more powerful and it came free with the scanner).
So I scan on vista, take to GIMP on linux for cropping, curves, a bit of Smart Sharpening
, and maybe colour-correction (although I've calibrated the scanner for slides and I'm getting better at scanning colour negs correctly as I learn silverfast), then I take it back to vista to print. The virtual machine makes it easy to copy/save files to the same location. Too easy.
I know GIMP and Gwenview aren't as powerful as PS or Lightroom or anything, but it works fine for me. Not being able to do all the fancy things is actually making me learn my cameras properly, getting it right in-camera precludes the need for too much PP.