One of the things that I believe is essential for a connected lawyer is a laptop. A laptop allows you to be out of the office, yet still connected to it. With the ubiquity of wi-fi hotspots and the emergence of high speed cellular data networks, you can usually find a connect just about anywhere that you are traveling, even if this means you have to stop at a Buffalo Wild Wings or a Starbucks.
Additionally, if you regularly scan your case documents or otherwise have electronic copies of them, you can easily carry all of your case information with you simply by taking your laptop with you. This is especially useful if you have to travel out of town to take a deposition. You can have your entire file with you, without carrying a single sheet of paper.
All in all, if you want to be away from the office and yet be able to work, a laptop is an essential item for you to have.