James has a nice list of Mac applications and I am using most of them. However, there is one missing: ChocoFlop, a CoreImage-based, realtime, non-destructive, high dynamic range Image and Photo Editing Application for Mac OS X.

Some of ChocoFlop's features:
- Very fast launch time (about 1 or 2 second on cheapest mac mini)
- Written from scratch for Mac OS X 10.4+
- No legacy or compatibility slow code
- Uses all hardware acceleration (CPU and GPU)
- Universal binary for PowerPC and Intel
- Uses CoreImage and custom OpenGL code.
- The download is about one megabyte (zipped) so far and will remain in that range (translation will probably increase this).

Yup, I am using it with no problems and BTW,  ChocoFlop and Flop.ca are not related :)