[jr2]

If you own a USB / External HD / or external drive of any sort (including MP3 players), check this site out, it pwns!! 

http://portableapps.com/  EDIT: Here's another: http://www.pendriveapps.com/ - with too many apps to list!  XD

Accessibility

    * Firefox Accessibility Extension - Make Firefox more accessible
    * On-Screen Keyboard Portable - Easily access an on-screen keyboard
    * Virtual Magnifying Glass Portable - A full-featured screen magnifier

Development

    * Notepad++ Portable - A full-featured text editor with syntax highlighting
    * Nvu Portable & KompoZer Portable - The easy-to-use Nvu web editor
    * XAMPP - Apache, mySQL, PHP, phpMyAdmin, etc in one package

Games

    * Mines-Perfect Portable - a classic hunt-for-mines game with advanced features
    * PokerTH Portable - classic Texas Hold Em style poker at its best
    * Sudoku Portable - the wildly popular and addictive puzzle game

Graphics & Pictures

    * GIMP Portable - Photo and Image Editor

Internet

    * FileZilla Portable - the full-featured FTP client
    * FireFTP Extension (for Firefox) - a lightweight extension
    * Gaim Portable - chat with AOL, MSN and Yahoo users in an easy-to-use interface
    * Miranda IM Portable - chat with AOL, MSN and Yahoo users in a customizable interface
    * Mozilla Firefox, Portable Edition - the award-winning web browser that's safe and secure
    * Mozilla Thunderbird, Portable Edition - the handy email client
    * Nvu Portable & KompoZer Portable - the easy-to-use webpage editor
    * PuTTY Portable - lightweight telnet and SSH client
    * Sage Extension (for Firefox) - A full-featured RSS extension

Music & Video

    * Audacity Portable - A simple audio editor and recorder
    * MPlayer Portable - Full-featured movie player with support for most video formats
    * VirtualDub Portable - video processing and capture utility
    * VLC Media Player Portable - An easy to use media player that plays most audio and video formats

Office

    * AbiWord Portable - a lightweight word processor compatible with Microsoft Word files
    * Lightning Extension (for Thunderbird) - A lightweight extension for your calendar and tasks
    * Mozilla Sunbird, Portable Edition - Calendar and task management with a familiar interface
    * Mozilla Thunderbird, Portable Edition (Address Book) - Email client's built-in address book with import/export functions
    * OpenOffice.org Portable - word processor, spreadsheet, presentations with Microsoft compatibility
    * Sumatra PDF Portable - a lightweight PDF viewer

Operating Systems

    * Mac-on-Stick - Run Mac OS Classic 7 portably

Utilities

    * 7-Zip Portable - File archiver and compressor
    * ClamWin Portable - Antivirus on the go
    * Command Prompt Portable - Simple link to a customizable command prompt
    * Eraser Portable - securely delete files and data
    * KeePass Password Safe Portable - Secure, easy-to-use password manager
    * PortableApps.com Backup - integrated backup utility bundled with the platform
    * PortableApps.com Menu - integrated start menu bundled with the platform
    * Toucan - backup, sync and encrypt for advanced users
    * winMd5Sum Portable - check md5 sums to verify files on the go

[ZmaN]

ahh sweet man thank you!  my mom had something like this on ehr flash drive i wanted it on mine but hers was factory installed...

[jr2]

Here's another: http://www.pendriveapps.com/ - with too many apps to list!  XD

[Solatar]

What's the difference between this and if I installed say...Firefox or GIMP on my flashdrive?

[jr2]

Installing it would edit the registry on your system, and FireFox would expect to use those registry entries on any system that you tried to use it on.  FireFox Portable (and other Portable Apps) are optimized for use on a removable flash drive.  See What is a Portable App?  and the following: 

Privacy: Does Firefox Portable leave behind any personal data?

A. No. Firefox Portable has its disk cache disabled. It uses RAM for cache. All your cookies and other data is self-contained on your portable device. At no time is any personal data stored on the local machine, so even if someone tried to find it with an undelete utility, there would be nothing for them to find.

This would not be the case if you installed Firefox onto your flash drive, and if you did that, your flash drive FireFox might conflict with your version of Firefox installed on the Hard Disk, possibly.  (If it tried to store settings, history, plugins, etc in the Hard Disk instead of the flash drive... esp if they are different versions.)

[achtung]

I used to use this stuff all the time in High School.  I'll probably start doing so again when Uni starts.