I have previously noted down Watson and GraphicConverter. These are nice low-price software packages running under Mac OS X. In addition, most software made by OmniGroup is first class. I have licensed OmniWeb, OmniGraffle, OmniOutliner, and OmniDisksweeper.
I'm not fanatical about using Free Software. I'm more on the lines of Open Source, but I also support shareware and commercial software. These have their advantages and disadvantages.
Mac OS X offers users all kinds of tools. The Fink project has ported a massive amount of free and open source software to Mac. MS Office is a massive commercial package. There are hundreds (if not thousands) of small software packages offering additional functionality for Mac OS X users. I hope the situation stays the same: there is enough room for all kinds of efforts in this garden.
What I'm against is using software as a strategic weapon, which leads to monopolistic aims and practices. The Free Software Movement has a point, which however is not realistic to implement. Thus, I'm ready to support all such software development which is based on open standards, free exchange of ideas, and free competition. No software patents, please!