Here's a list of a few well-known options in each "editors" category I've listed so far (not including the behemoth Microsoft or Adobe apps that everyone knows but probably can't afford). If you have more programs to add, please comment! If you want to review a particular program or compare similar programs, please do so in a new post!
Editors: Audio
Editors: Code
Editors: PDF
- PDFpen ($50)
- Skim (Free)
- Preview (included with Mac OS X)
Editors: Pictures
Editors: Word Processing