Lightzone from Lightcrafts has been around for a year or so and is another of the new breed of raw image file processors like Adobe's Lightroom beta and Apple's Mac-only Aperture. I looked at it a while ago and it was only available on the Mac, but now it's available for the PC too as a 30 day free trial.

As I understand it, Lightzone is like Lightroom and Aperture in that it saves instruction sets or processing instructions rather than having to output the raw image as a Photoshop or tif file. Unlike those products, its processing instructions can include selection-based editing. I've only tried it for half an hour but one especially interesting feature is how it deals with versions and I really like the tone map for levels adjustments - see this screenshot. It's defintely worth trying.

Also see Outback Photo.