I love products that help me manage workflow, and to be more efficient. No product can MAKE you be productive and efficient, but they can help. I've used DayTimer, Franklin Planner, Outlook and Palm Desktop. I've read Steven Covey and David Allen. I've learned something from all of them over the years. I've become mostly aligned with David Allen's Getting Things Done approach. If you are not familiar, do yourself a favor and check it out.
About 6 months ago I learned about Asana. It is a web-based team task management system. I've not adopted their model to use it to replace inter company email yet, but maybe I should. Asana is flexible, and yet offers enough structure & assistance to get you started with ease.
If you are in the market for something like this, Asana might be the answer - and it is free for small companies and very reasonably priced for others.
My favorite tip I've learned over the years is a way to manage tasks/questions I've delegated to others. David Allen calls it @Waiting For. I just use Waiting For. In our case it is a tag in Asana, but there are many other ways to use this idea.
Good luck and enjoy!