Originally posted by Kraftman
Aperture, adobe stuff (lightroom, photoshop), Pixelmator, etc. There's also many freebies (you can google all this shit yourself, though) and obviously you can easily build Digikam, gimp, cinepaint, etc on a Mac via fink/macports and i think there may actually be a version of gimp that uses cocoa, although i've never used it, personally.
The fact that i can run most of the software i would be running in Linux, on my Mac Desktop is nice, as well. So even if you were to sit here and argue by comparison, it is a moot point because on a Mac you can run most *nix apps, anyway. But putting that aside, Digikam isn't as good, and is not at feature parity nor usability to some software available for Mac. It's not like i haven't looked at this myself, being as i have both sitting in front of me.