I know I have some freaks among my readers that like to use an usb stick to have some of their beloved applications at hand or start them from their for security reason. Wikipedia.org has a nice list of portable applications that can be run from a portable device. Every application is sorted into one of nine categories like Networking and Internet, Password management and Document editing .
Take a look, everything is linked to its own wikipedia site and / or the developers website.

Use PStart to access your portable devices
Portable Computer Software Collection Liberkey
Software Management: Sysinternals And Nirsoft System Control
Pricelessware 2006 Freeware list
Opera 10 Portable
very useful. an additional portable usb device might be required to install every handy application mentioned. ;)
Oh come on. We’re not freaks :)
Cheers for the link…