Acrobat Reader (internet link) Pretty much everyone has a copy of Acrobat Reader these days. You need it to read PDF files. If you haven't got a copy, then be sure to download one. If you don't like Acrobat, you can also use the free Foxit Reader program to read PDFs.
Graphic Workshop Pro - "Graphic Workshop Professional is the image management package for Windows. Whether you'd like to browse your image collection and view pictures, convert between formats, print your graphics as hard copy, acquire images from a digital camera, maintain a sophisticated keyword database, decode pictures from the Internet, process and fine tune your photographs... the list of Graphic Workshop's functionality can run for pages." This software is shareware. The program is complete and not time-limited. Install and try it out on your computer.
Imatch - Catalog your digital photographs, and categorize them for instant retrieval. Evaluation copy (time limited) is free, buy full copy online.
Panorama Factory - "The Panorama Factory from Smoky City Design, LLC is a panoramic stitching program for Windows 95 / 98 / ME / NT / 2000 / XP. It creates high-quality panoramas from a set of overlapping digital images. The Panorama Factory transforms (warps) the images so that they can be joined seamlessly into panoramas whose fields of view can range up to 360 degrees." Version 1.6 is freeware, later versions are shareware (download a demo which puts a watermark on each image, if you like it, register and the watermark disappears).
PowerPoint Viewer - this viewer will view PowerPoint 97 or later files (including the PPTX/PPSX format used by Office 2007/2010).
Troopmaster / Packmaster - Software for organizing your troop or pack records. Demo available for download.