I've been using digiKam for a while. In fact the only reason I have KDE libs on my system is to run digiKam. I've tried lots of organizational programs, and they all have limitations, but digiKam is good at handling RAW images (including custom color profiles), has decent editing capabilities, and makes it easy to apply transformations to image sets. It also has no problem dealing with a directory full of images, and it will only modify them when you tell it too (a problem I had last time I tried F-Spot)
I know this is an article about Shotwell, and it is scheduled to have RAW support and a 16bit pipeline in the future, but I think it needs to mature more before I give it a try.
Anyhow, I think the grumpy editor reviewed digiKam a while ago (like in 2005), but I am quite happy with it now