John Please look at this..

Here is a list of apps that might be usefull and could be added to the different catagories on this site.
First this one might or might not be possible to make portable.
Operating Systems:UbuntuWhich is open-source and here is there site description "Ubuntu is a community developed operating system that is perfect for laptops, desktops and servers. Whether you use it at home, at school or at work Ubuntu contains all the applications you'll ever need, from word processing and email applications, to web server software and programming tools.

Ubuntu is and always will be free of charge. You do not pay any licensing fees. You can download, use and share Ubuntu with your friends, family, school or business for absolutely nothing.

We issue a new desktop and server release every six months. That means you'll always have the the latest and greatest applications that the open source world has to offer.

Ubuntu is designed with security in mind. You get free security updates for at least 18 months on the desktop and server. With the Long Term Support (LTS) version you get three years support on the desktop, and five years on the server. There is no extra fee for the LTS version, we make our very best work available to everyone on the same free terms. Upgrades to new versions of Ubuntu are and always will be free of charge."
Utilities:Winpooch Which is an Open-source Antivirus just like Clamwin.
Valrind An open source alternative, Valgrind also detects leaks and other memory related programming errors. But, it also detects threading bugs and includes a call-graph profiler that detects bottlenecks in code. as well as threading bugs.
Office:Kexi Kexi is a Free/Libre and Open-Source integrated data management application, a long awaited Open Source competitor for products like Microsoft Access.
Open Workbench Open Workbench is an open source desktop application that provides robust project scheduling and management functionality. Already the scheduling standard for more than 100,000 project managers worldwide, Open Workbench is a free and powerful alternative to Microsoft Project.
Graphics & Pictures:InkscapeAn Open Source vector graphics editor, with capabilities similar to Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format.

Inkscape supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface. It is very easy to edit nodes, perform complex path operations, trace bitmaps and much more. We also aim to maintain a thriving user and developer community by using open, community-oriented development.(look at Screenshots
Tuxpaint Tux Paint is a free, award-winning drawing program for children ages 3 to 12 (for example, preschool and K-6 in the US, key stages 1 & 2 in the UK). It combines an easy-to-use interface, fun sound effects, and an encouraging cartoon mascot who guides children as they use the program.(looks fun if u get bored)
Internet:Adium Adium is a free instant messaging application for Mac OS X that can connect to AIM, MSN, Jabber, Yahoo, and more.(check outScreenshots)
Music & Video:Galleon Galleon is a free open source media server for the TiVo® DVR which allows you to enjoy many kinds of content and interactive applications right on your TV. The server runs on your home computer and organizes your media collection so that they can be viewed on your home network. Galleon also brings Internet content and applications to your TV.
Miro Miro, an open source program that turns your computer into an internet TV. Miro has 2,500 unrestricted channels with a huge selection of HD content. Plus, you have access to any publisher with video RSS feeds, including anyone on YouTube, Revver, Blip, and many, many more.