Linux is great, but it is a little lacking for digital photography. I used Linux for quite some time and my favorite software for RAW workflow was
digikam. However, last time I used it, it was quite buggy. Maybe that has changed. There is also UFRaw, but I found it a little inconvenient to use. GIMP will work as a replacement for Photoshop, but it lacks 16-bit support. If you want a commercial solution, Bibble runs on Linux as well.