Here is a list of tools that I use. The following may have to do with web design and development, or system administration.
This is just the beginning. I will update this more in the future.

jQuery UI
This is was introduced by a coworker while building a web UI. Their examples and theme builders a superb.

Logstalgia is a pretty slick application to show your web server traffic in a fun way. How useful is it? Not sure, but it helps visualize the traffic for those who are not familiar with the statistics provided.
Here’s a how to install/example video: