The Web Developer extension adds various web developer tools to the browser.
FireShot Webpage Screenshots captures webpage screenshot entirely (see demo: http://bit.ly/RlBQMV)
The screenshot can be quickly annotated and:
+ Saved as PDF/PNG/GIF/JPEG/BMP
+ Sent to clipboard
Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...
This is a cut down version of IE View by Paul Roub, which is 47.4 KB. All the same UI and features are there. It has a right click menu item to open a page in IE and a list of sites to always open in IE. It can close tabs automatically and send...