Open Source or Free web aps that make your life easier

[Andrew Schreiber]

Foxit Reader A lighter weight alternative to Adobe's PDF reader. The free version works wonders on older machines. Not Open source though.

For really great ad blocking and pop up blocking lynx works for me.

I will throw another vote in for Ubuntu, having a system be up all the time is a nice thing. My current uptime is about 42 days and the last time I turned it off was due to a power outage.

On Ubuntu my list of handy apps are:
libsensors - Command line tool for checking temperatures.
grep - Command line text searching tool. (http://schreiaj.ath.cx/FRC/ is done entirely using grep at the moment)
curl/wget - Command line tools for getting web pages.
Apache - Best Web Server EVER
Webmin -For people who dont like terminals, web based server configuration.
MySql - Amazing database for storing info, many commercial sites use this as their back end.
PHP - widely-used general-purpose scripting language that is especially suited for web development and can be embedded into HTML.

That is all I can come up with at the moment.