After we hung up, I got to thinking a bit more about the questions Brooks asked and my reply. Hindsight being what it is, I would like to amend or add to my comments.
The third topic I would like to cover is a furthering discussion of the use of Open Source tools for image processing.
I believe that commercial tools are valuable to commercial artists. These kinds of tools clearly define the limits of creativity. Yet, they provide a level of stability and assurance that a commercial artist can rely on. Once the investment in money, time, and energy is made, the artist can free themselves to work within the boundaries set by the commercial tools.
Open Source tools sometimes aren't as well "packaged" as their commercial equivalents. One thing that is attractive about deploying Open Source image processing is that limits are less clearly defined. To me, this means the boundaries of capability and creativity can be pushed well beyond the typical limits set by commercial offerings.
An analogy that might help describe my thoughts and feelings about commercial verses Open Source tools is this. There are woodworkers who go down to the local tools supply and buy the tools they need. The barrier to entry is money. Once the tool is in hand, they can return to their craft and continue creating whatever it is they wish to create.
On the other hand, I know a number of woodworkers who in some cases make their own tools. For instance, tools that help make a new version of an old molding for which there is no longer a pattern. For these artists, the barrier to entry is time. That is, the time it takes to make the tool that will do the job.
Similarly, in my use of Open Source tools and technologies, I feel there are few limits to creative expression. Sure, it can take time to seek out a set of applications, learn their use, and then apply them to a project of images. Once I'm done, I have pushed myself and my images well beyond the boundaries and capabilities of similar commercial tools offerings.
Perhaps a few links are in order. These might help give you a sense of where I am working today. Some of these tools are very "raw" and unpolished. Others are generations old and match or exceed the stability and capabilities of their commercial equivalents. The image above was created using a combination of nearly all of these tools. I hope you find them useful.
Applications that extend the capabilities of a normal digital point and shoot beyond any DSLR (regardless of price) - CHDK
Noise reduction software - Greycstoration
An image processing application - Gimp
High Dynamic Range control software - Qtpfsgui
Image stitching software - Hugin