Mac/iOS: We've mentioned that regular writing can have big mental and emotional benefits, and even how keeping a work journal can help your career, but to really get into the habit of regular writing, you'll need a tool that encourages you to do it -- one you'll enjoy using. If pen and paper doesn't suit your fancy, try Day One, a journaling app that looks great and helps you keep track of every entry you make.Day One isn't cheap -- the desktop app for Mac will set you back $10.49, and the iOS app for iPhone and iPad will cost you $1.99. For that price, however, you get a very robust writing tool that lets you jot down your ideas freehand in the app or through a menubar utility, quick search all of your current and previous entries, a calendar view so you can easily see how well you've been keeping up with your writing, and even reminders to make your daily entries. The app even has command-line support, so if you spend your day in Terminal windows, you can still get a little writing done.
The app also supports iCloud (coming soon) and Dropbox sync so you never misplace your documents or updates, and if you have the mobile apps and the desktop apps, they'll sync with one another so you can take your stories or journal entries on the go. If you're an avid writer or just want to get into writing regularly, Day One is a robust app with a good-looking UI that can help you get started.