If you do alot of digital photography, you probably have certain tools that you like to use in you "digital darkroom". Photoshop is usually considered THE tool for "serious" photogeeks. Yes, I know, it doesn't run on Solaris (or Linux), but I when I am working on photos, I want the best tool for the job and am not going to let OS religion dictate my choice of tool. However, Photoshop CS is also seriously expensive for the full blown version.
The Gimp is a very powerful tool that is included in Solaris 10 and on most Linux distros. Personally, I don't care for the Gimp interface, but that's not to say it won't do the job. GIMP does have a nice interface for adding extensions and there is a growing community of GIMP extension developers who are always adding nice enhancements. Most digital workflow steps can be performed in the Gimp just as in Photoshop. Its a matter of choice and convenience.
One thing that the GIMP and Photoshop do not offer is a way to manage huge libraries of photos. I have thousands of images on my hard drive and searching through lots of subdirectories and looking at non-descriptive filenames (ex: DSCN01234.JPG) is not a very efficient system. There are alot of packages out there for managing digital photo libraries. If anyone actually reads this, maybe I will get a bunch of suggestions for OpenSource photo managers that I can try out and report on later.
I have always liked using ACDSEE, it is very fast, it has nice browsing features, has great archiving, backup and restore features. It also includes an editor which can do all of the most common digital "tweaks" that one usually performs.
My new favorite tool is Picasa2 from the folks at Google. The interface is slick, the editing tools are more limited than those from ACDSEE, Gimp, or Photoshop. However, the editing features that they do offer are really easy to use and I have had excellent results using Picasa2 to adjust my photos for web publishing. It has nice features for archiving, backup/restore, and searching. I highly recommend using this if you keep your photo library in Windows and need a good utility for managing and doing basic "digital darkroom" operations.
Here is my photo gallery, most of the photos in this were edited with Photoshop, but I am starting to use Picasa2 more and more now.