Firefox add-on

This has to be one of my favorite add-ons for firefox it's call Stylish.
Stylish add-on link
Then with Stylish installed use a theme from http://userstyles.org/ you can change the look of how you view sites.

The reason why I like it so much is with the right theme it's so much more pleasant on my eyes to view web sites, No more harsh white backgrounds or generally painfully bright sites for me.

AntiRSI

Mac OS X only: Freeware program AntiRSI is designed to help you avoid repetitive strain/stress injury at your computer.

AntiRSI schedules inobtrusive 13 second pauses every four minutes (if you don't take your hands off the keyboard for the full pause, it restarts the timer). Likewise, breaks happen every 50 minutes, and last for 8 minutes (again, you have to stop typing for it to count). Lastly, you can adjust the pause and break intervals, as well as the pause and break times to whatever you want.
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Help prevent RSI

UserHealth
This program is for computer users that spend several hours in front of the computer without breaks or pauses, often without realising it. Its purpose, as the author puts it, is to be your silent health and sleep supervisor. It keeps track of your active computer usage time which can also be displayed as statistics to show you how long you have been active on the computer. What it then also does is provide you with regular health, pause, or sleep messages to remind you to take a break. These messages can be displayed like small popup windows in the right corner, a topmost window or a sound. It also includes a shutdown feature that can log off/shutdown your computer at a given time.
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BreakReminder
This software was created mainly for those who never know when to stop working and relaxing for just a short while.BreakReminder is a small program that reminds you of taking breaks while sitting at the computer. This way you won't exhaust yourself and your productivity will increase.

Select the time in the drop down box and click on Start button. The timer will start the countdown. You will see the timer time in the progress bar. Now you can minimize the program window or switch to any other application. Once the time is up, the program will display a dialog window with the break reminder message.
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Big Stretch
This application will remind you to take frequent breaks from work to prevent RSI.Big Stretch is a free simple reminder tool that prompts a user to take regular breaks and helps prevent the symptoms of RSI. Alternatively, you can use it as a simple reminder to notify you when it's time for your coffee break!

The program will sit happily in your system tray (where the little icons are in the bottom right hand corner of your screen.) until a predefined time period of your choice arrives at which point a “balloon” will appear offering either RSI tips and advice or a message of your choosing.
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Nutrition Facts software

Nutrition Facts is free software for Microsoft Windows. It will run on any operating system that supports Microsoft .net 2.0, including 98, ME, 2000, XP, Server 2003 and Vista.
Nutrition Facts provides detailed nutritional analysis on over 7,500 foods. Simple interface resembles the standard nutrition label found on most food items. Foods can easily be searched and quantities changed to adjust the nutritional data. Great resource for those on diets. Based on the United States' nutrition database.

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