Floyd L. Davidson
There are other requirements. One is being able to *use* an OS to *make* better tools.

nospam
good tools can be made for any os, and in fact, it's much easier to do that on mac and windows than it is on linux because there's so much built into the operating system itself for apps to use, especially a mac.

pixelmator (mac only), for instance, is a reasonable alternative to photoshop because much of the image processing in it they got completely for free since it's just an api call. it doesn't do everything photoshop can do but it does quite a bit.

Savageduck
Pixelmator is an astonishingly good value and performer, it certainly out performs GIMP for those Mac users looking for an Adobe alternative.