Here are some of the cool development tools on the internet:
ThunderMain's Full Source and Toggle
Borders IE extensions - allows you to see the IE processed source and borders
around tables, divs and spans.
A free tool for creating UI automated tests using Internet Explorer
XPath Builder - A very simple tool with source code
Comment Reflower - Allows you
to change the format of comments
ZaneBug - An improved nUnit interface
Wink - "Wink is a Tutorial and Presentation
creation software, primarily aimed at creating tutorials on how to use software (like
a tutor for MS-Word/Excel etc). Using Wink you can capture screenshots, add explanations
boxes, buttons, titles etc and generate a highly effective tutorial for your users."
This list will grow over time.