Want to use a USB thumb drive to take all your applications as well as your settings wherever you go? Check out the
Portable Apps Suite. They have many optional apps, but the standard package includes:

Portable Firefox (web browser), Portable Thunderbird (email client), Portable OpenOffice.org (office suite), Portable AbiWord (word processor), Portable NVU (web editor), Portable Sunbird (calendar & task list), Portable FileZilla (FTP client), Portable Gaim (instant messenger) and will fit on a 256Mb USB thumbdrive.

Read more at: PortableApps.com