I try to use freeware and open-source software whenever possible. I don't mind paying for a bit of good shareware either. Here are my favorites. I've skipped the widely-known ones like Firefox and iTunes:
My dissertation is primarily written with NeoOffice, the Mac version of OpenOffice. NeoOffice is available through a number of mirror hosts, one of which is my school, the University of Wisconsin.
For notetaking, outlining and keeping track of snippets, I use Voodoopad. It's not free but I'm glad to support it.
For the huge bibliographic undertaking of dissertation-writing, I paid for Bookends. I could not be happier, I recommend this application to every student and professor I know.
For day-to-day organization, I use iGTD and Deep Notes.
When you're teaching statistics, Tex is indispensable for formatting equations, especially those involving summations. It's available for all platforms.
UPDATE: I just discovered Graph Sketcher, a really nice program for making simple examples. The advantage over spreadsheets and Stata is that you can define your data very "casually," or even just draw the lines on the graph for illustration. (GraphSketcher is not freeware, it requires registration and leaves watermarks during the trial period).
This webpage was designed with SiteStudio and edited with Taco HTML Edit. SiteStudio is a limited but very simple design program for beginners, with built-in templates.
For news gathering, I use NetNewsWire Lite, although there are now many great free clients and browser-based solutions like Google Reader, Bloglines, Vienna, RSSOwl, and so on.
Some other small but helpful applications for Mac:
MenuShade
Huevos
Mail.appetizer
Quicksilver
Find Free and Open Source Software:
Many people compile "favorite freeware" lists, or run sites that offer a new application every day. Here are a few to look at. The first two cover all operating systems, the others are Mac only:
Best of the Best Free and Open Source Software
SourceForge
Open Source Mac
FreeMacWare
Essential Mac applications






