HTTP Fox is a pretty neat firefox extension. It allows you get the details of the http transaction with the web server. Some of it overlaps the functionality of firebug. The extension is fast and provides some nitty gritty details that are sorely necessary when debugging web applications.
It provides a detailed view of the headers, querystring, cookies, post data, and the content. It also provides the trace functionality, so you can see a detailed view of all the requests made to get the content on a page. The elevator evaluation is that it is a cool tool which will come in handy when you most need it.












