First up, TextExpander. This is a key macro utility. Think live templates for your entire operating system. You save whatever text you want to type under an abbreviation and TextExpander automagically expands it for you inline. For example, I type the words "No Fluff, Just Stuff" a lot, so I have a shortcut for it. I'm genetically incapable of spelling the word "Selenium", so I have another for that. I also have chunks of command-line goodies that I used to have as bash aliases, but I got tired of fighting the single-double quote war with bash. Now, I just type the abbreviation to get this:
What's even better is that you can determine where you want the cursor to end up by placing a magic marker there. For my Ruby on Rails talk, I need to create a database keyed to the city I'm in, so I use this TextExpander goodie, which leaves my cursor right before "_development".
svn st | grep '^\?' | tr '^\?' ' ' | sed 's/[ \t]*//' | sed 's/[ ]/\\ /g' | xargs svn add
What's more, you can create abbreviations for stuff like dates. Life's too short to be typing the bloody date all the time, so it looks like today is 2007-10-25.
/opt/local/bin/mysqladmin5 -u root create %|_development
TextExpander is a great example of a "$20-ware" Mac OS X utility (see, I just typed "Mac OS X" with an abbreviation). There are some others like this (like Typinator), but I prefer TextExpander.