There are thousands of programs out there for Mac freeware and shareware, here are some of my favorites:
Graphics
Photo and Image Editing
- The Gimp 2 is free and really good, but a bit hard to learn.
- Grab is a screen capture utility that works great
Desktop Publishing
- Fontbook - for managing fonts on your computer
Web Authoring
- JAlbum - for Web Gallery creation. Awesome program that is very customizable
3d Animation
- Maya PLE (free but stupid water marks)
- Blender
Video Production
- Grab can be used to capture an image of a Video frame when you use VLC DVD player
- Mac the Ripper for ripping from a DVD
- ffmpegX for encoding a riped file
Office Suites
- OpenOffice is free and works incredibly close to Microsoft Office
Computer Utilities
- Stuffit for unzipping files
- Preview (Part of OSX) works just fine for reading pdf files
Spyware & Security
- Turn on and configure your firewall :-)
Multimedia
- VLC for playing DVD's (Besides the native player that comes with it)
- DiVX for movies
- iTunes (Part of iLife 05 and free to download) for mp3 playing. Ok, but all I am aware of
Internet
- Firefox For web browsing (Safari is good as well)
- iChat (Part of OSX) works just fine for instant messaging
