Vitamin-R - The best Pomodoro app for Mac
Other than the GTD methodology, the Pomodoro technique is my favorite productivity tool for actually getting stuff done. In short, it's a way to maximize the time where you're highly concentrated and productive and minimize both internal and external distractions. It helps you achieve this by time blocking (typically 25 min intervals) and a strict set of rules that help you keep focused. I've been using it for a couple of years now and it really complements GTD well....