Eventually, though, I switched to using a Mac. And, just as with my PC, I wanted to find a lot of open source software to meet my basic computing needs. I didn’t want to shell out the big bucks for Office or other such expensive pieces of software - I’d already spent enough. So I went hunting.

What follows is a list of twenty five pieces of software that are the cream of the crop of open source software for Macs. Not only is every piece of it free, many of them directly replace expensive software packages.

1. Firefox
Replaces Internet Explorer and Safari
Safari is a very solid web browser out of the box, but it’s not nearly as extensible or useful as Firefox. With add-ons like Book Burro, FareFirst, and Package Mapping, plus the speed and reliability I’ve come to expect, Firefox is the only web browser for me.

2. Quicksilver
Unique but useful (productivity)
Quicksilver lets you set almost anything you can imagine in Mac OS as a keyboard shortcut. This allows me to do things like start iTunes and have it auto-play a specific podcast with a specific keyboard shortcut (I have one that auto-plays This American Life, for example). It’s a bit complicated at first, but once you get used to it, it makes you feel massively productive and it becomes almost an essential part of the OS.

3. Thunderbird
Replaces Mail
For most purposes, the default Mac OS Mail does the trick, but I find Thunderbird essential because it allows me features like auto-replying to certain kinds of messages and far better IMAP support, and it’s faster, too. Even better - it works identically both on my PC and on my Mac.

4. Sunbird
Replaces iCal
I like iCal, but Mozilla Sunbird does one thing that iCal doesn’t - two-way syncing with Google Calendar. When I’m traveling, I’ll use Google Calendar at any terminal I’m at to print out tomorrow’s schedule, make little changes, and so on. When I get home, it’s just a click of a button and it all syncs up with Sunbird. That’s an amazing feature for me and it makes Sunbird far superior to iCal.

5. AbiWord
Replaces Microsoft Word
This is, by far, the best open source word processor for Macs. It functionally replaces Microsoft Word for almost every purpose I’ve come across and has a fast and slick interface to boot. This is the word processing program I used to write my book with, in fact.

6. OpenOffice
Replaces Microsoft Excel and PowerPoint
Need to make spreadsheets or presentations on your Mac? OpenOffice provides the tools you need for that (as well as word processing, but I prefer AbiWord for that). I often use OpenOffice Spreadsheet for the number calculations you see on The Simple Dollar, as well as using it for tracking my net worth (as in this tutorial I wrote).

7. Seashore
Replaces (for most uses) Adobe Photoshop
This is a fairly simple image editor that takes care of most of the basic uses of Photoshop and is simple enough for most users to pick up. This is a great solution for those who want to do simple image manipulation but don’t want to shell out the big bucks for Photoshop.

8. Scribus
Replaces Adobe Pagemaker (desktop publishing)
I’m actually elbow-deep in Scribus right now as I work on a special side project. It’s a very powerful desktop publishing program, giving you tons of freedom to lay out pages however you like. Another use: I’m thinking about making a family newsletter to ship out in the Christmas cards this year.

9. Adium
Replaces iChat
iChat is pretty slick, allowing me to chat in AIM and GTalk at the same time, but what about all of the other chatting protocols out there. Adium allows you to be on YahooIM, Windows Messenger, AIM, ICQ, and several other messaging services at the same time with the same program.

10. OneButton FTP
Replaces “command line” FTP
On occasion, I need to FTP some files from one place to another (usually from one computer to another within our home network, when I’m too lazy to use a memory stick). OneButton FTP does the job in the simplest and easiest way possible - much easier than the default “command line” FTP.

11. Audacity
Replaces/supplements GarageBand
Need to make audio recordings of your own? All you need is a microphone of some sort and Audacity - and you can create podcasts, record music, or pretty much anything else you can imagine. I’ve actually considered using it to read aloud some bedtime stories for my kids in advance of any traveling I might do.

12. Cashbox
Replaces Quicken
This is a very nice personal finance data manager for Mac OS. It doesn’t have quite all the bells and whistles of Quicken, but it provides a strong feature set and a huge number of different views of your personal finance state. If you’re a Quicken fan but don’t want to drop the cash for a Mac version, look into this one.

13. Vidalia
Unique but useful (privacy)
Many people are concerned about online privacy and don’t want their IP address shared with web sites that they visit or file servers that they access. Vidalia easily allows you to use proxy servers for your accessing needs, enabling you to disguise your computer on the internet.

14. Books
Unique but useful (book cataloguing)
This one’s just for fun, but I’ve found it very useful. It allows you to catalogue all of your books, create reports, and so forth. I’ve been using it heavily in conjunction with PaperBackSwap to help me as I read through a pretty big pile of classic literature.

15. Bean
Replaces TextEdit
I use this software for the editing of virtually every post that appears on The Simple Dollar. It’s a slick little editor with features like automatic word counting that really help when you’re trying to keep some semblance of control on the length of your articles.

16. GanttProject
Replaces Microsoft Project
This is an excellent tool if you’re involved in the management of large projects with many staff members, particularly if budgeting is tight (as Project can be expensive). One of my closest friends uses this for mission-critical projects in the workplace.

17. Nvu/BlueGriffon
Now: http://www.macupdate.com/info.php/id/15699
Soon: http://bluegriffon.org/
Replaces Dreamweaver (HTML editing)
I prefer coding my HTML by hand, but many people prefer the aid of a tool to help them with layout, and that’s what these provide. Nvu is a bit outdated but is still very useful - the creator has moved on to a new project, called BlueGriffon, which should be available soon.

18. Blender
Unique but useful (3D graphics creation)
Blender is a magnificent tool if you like tinkering with 3-D graphics creation. It’s perhaps overkill for most people, but if you’re involved in graphic design at all, using and knowing Blender can be invaluable.

19. Colloquy
Unique but useful (IRC)
If you chat on IRC, Colloquy is essential software. For the uninitiated, IRC is a very large network of chatrooms on various specific topics, often developing their own culture. Colloquy is a wonderful solution for IRC chatters on Macs.

20. FreeMind
Unique but useful (brainstorming)
Whenever I’m struggling to organize my thoughts and ideas, I open up FreeMind. Basically, it’s a tool that lets you toss out your thoughts in an unorganized structure, then build connections between them however you like. I often use it for posts where I have a collection of thoughts and research notes, but I haven’t really decided how to order them or tie them all together. It’s brilliant in any brainstorming setting.

21. Celestia
Unique but useful (planetarium)
If you’re a space buff (like I am), Celestia is incredible software. It’s a great way to create star charts, help you identify good nights for viewing constellations and other stellar objects, and simply stumble around different views of the sky. I simply love looking at the night sky, and Celestia is a wonderful free companion for this hobby.

22. Transmission
Unique but useful (file sharing)
Many people like to upload and swap their own files with other users, such as live recordings of concerts, recordings of their own performances, free application software, and so on. BitTorrent is one of the most popular protocols for doing this, and Transmission is easily the best of the open source Mac clients for swapping them.

23. MacLibre
Supplements Software Update
Many of these software packages are updated fairly regularly by their authors. MacLibre serves as something of a “Software Update” tool for these things, fetching updates for you and helping you to easily install them with just a click or two. It’s a great way of keeping up to date on software updates for open software on a Mac.

24. Aleph One
Like games like Quake and Half-Life? Aleph One is an excellent open source game in this vein, available for the Mac. The graphics are a bit on the simple side, but online play is quite slick and one can’t argue with the cost.

25. Battle for Wesnoth
The final choice on this list is a turn-based strategy game with a fantasy theme. Battle for Wesnoth presents you with a wide array of scenarios that require you to take turns moving pieces around the landscape, thinking about your moves, and engaging in skirmishes. This one ate up a lot of my hours a few years ago!