Update (12/4 10:15am): TextExpander 3 + custom keyboard now available for $1.99 (Reg. $5) on iOS as well.
Typing out the same replies and contact details every day is the kind of time-sapping task that TextExpander cuts down on. 9to5Toys Specials has this award-winning Mac productivity app for $22.
This neat utility lets you save all the text snippets you use regularly, and assign a shortcut to them. For instance, instead of typing out your email signature, you could just write “eml” and TextExpander will do the rest. This works pretty much everywhere in OS X, and you can automatically fill in the current date and time. As you type, the app looks out for and fixes the typos you make most often, and it will automatically fill out forms with your details. The current version also intelligently suggests the shortcuts you might want to use, based on your usual style of doing things. It is an amazing time saver, and it comes in several different languages.
Order now to save 51% on the regular price for the app.