I've decided that, for the edification of everyone who reads my blog and has a mac (I think that might be one person =]), I'd put together a list of my favorite apps and tips for Mac. All free, too, so you don't have to pay for cool stuff =]
Firefox: Duh. Favorite browser of all time. It's cross-platform, OSS, fast, and has extensions. I personally use AdBlock Plus (a must-have for browsing), NoScript (ditto, although this one is probably not for your grandma), Web developer toolbar, Firebug (both essential for web development), TrackMeNot (which searches Google with random things to keep them from being able to track what I actually searched), CustomizeGoogle (more security stuff), and, lastly, Cooliris--a must-have for eye-candy lovers and people who need to browse images fast. Get it and try it out--there's nothing like it.
Speaking of web development, TextWrangler (http://www.barebones.com/products/textwrangler/) is my programmer's editor of choice. It's a free dumbed-down version of BBEdit, but it does everything I need it to (syntax highlighting, multiple files, find-and-replace) and lots more (execute a file from the editor, find-and-replace across multiple files, etc.).
The other app I use for web development is Macfusion (http://www.macfusionapp.org/). This lets you mount SSH and FTP shares as volumes on your Mac and interact with them with the Finder. It makes copying and stuff really easy. And if you need to make some quick change to a file, it's fast, too.
NeoOffice (www.neooffice.com) is a port of OpenOffice to OS X. It's a bit faster, and a lot fancier, than OpenOffice, but it's only up to version 2 of OO right now. I use it as a substitute for Word.
I also use the Visor add-on for Terminal that I wrote about a few posts ago. It's nifty to the extreme.
Another add-on I just discovered is GeekTool: http://projects.tynsoe.org/en/geektool/ It lets you run scripts and a lot of other things at certain intervals. Currently I just have it running 'uptime' on a window on my desktop, but I can imagine all the nifty things you can do with it. Like using curl and grep (or perl) to download a webpage and pull something out of it (e.g. sale of the day, etc.) and display that on your desktop.
And, finally, there's WhatsOpen (http://www.agasupport.com/?page_id=72), which displays all your open files. You can set it to display only a particular volume, so you can see which apps need to quit so you can eject a disk. If you don't like the command line, this is a nice tool. (For the command line junkies, try lsof and pipe it through grep. For example, lsof | grep WhatsOpen).
Hopefully someone will get something out of this =]