If you have ever tried digital editing of photos, you would know that Adobe Lightroom is the best software for that. No other software even comes close to offering the extensive features found in Lightroom.
The bad part is that the current version of Lightroom (version 2) costs $300, but the good news is that you can download the newer version (version 3) for free and use it till April 2010. It is ofcourse a Beta version but comes with all the goodness. It is meant to be an evaluation version before Lightroom 3 is officially fully released in a few months.
Download Adobe Lightroom 3 here.