Note: This product has been discontinued by the vendor and is no longer offered (3/26/13).
Suppose you have several documents in different formats, and you want it all wrapped up in one pretty PDF or Microsoft Word doc package. You'll find gDoc Fusion ($65 for personal/student license, $100 for business) an excellent choice. You can combine documents of just about any type, including PDFs, Office files, graphics files, and many other file types--200 in all. You'll be able to include not just the most common ones, but long-forgotten ones as well, such as from the XyWrite, Samna, and Ami Pro word processors, Multiplan spreadsheet, and more. If you have a word processing, presentation, spreadsheet, or graphics document, there's a good chance gDoc Fusion--available in 32-bit and 64-bit versions--can handle it.
To combine documents, drag and drop them into gDoc Fusion, then remove or reorder pages you don't want. You can also rotate pages, crop them, re-order them, annotate them, and then save in either PDF or a Word format. It's as simple as that. There are nice extras here, such as the ability to compress files and encrypt them. The files I tried converting with gDoc looked as good as the originals.
If you find yourself needing to create new documents out of multiple existing ones, you will find gDoc Fusion a big time saver.