Intellitabs is an addon for Microsoft Office putting a seamlessly integrated set of tabs to Word, Excel, and PowerPoint for fast switching between documents. With Intellitabs you can customize what data is shown on the tabs and in their tooltips (e.g. author, word count, file size, etc.), and you can save a group of tabs as a "session" so all of the documents can be opened at once. Intellitabs isn't free--it will cost you $19 for the Standard edition of each flavor (Word/Excel/PowerPoint) or $29 for Professional, or you can get all three Pro addons in a $49 bundle.