Fantastic list of full-arensal productivity tools from Matthew Toren including workflow, project management, keyword research, social media, and even stress reduction!
"Time is of the essence when you're running a business. As an entrepreneur, you're responsible for a variety of duties -- content creation, trend tracking and finding leads, just to name a few. And there often isn't enough time in the day to get everything on your checklist done. There is something to be said about hard work, but one thing is even better: working smart."
At the risk of being obvious, I'd add Trello and Google Docs as well.
Any other favorites?