Fiddler Is AWESOME!

Hanselman should add this to his Ultimate Tools list: Fiddler by Eric Lawrence of Microsoft (this thing rocks!)

Why would you need something like this? To view raw HTTP Requests and Responses, for one. It integrates right into Internet Explorer, and will take care of proxy configurations on the fly (so all you do is click a toolbar button, the app launches, and then captures all requests/responses going forward for you to inspect).

When developing web applications and web services, you often need to review what is being sent to the server (including headers) and what is being received. IE doesn't really let you do this by itself, so that is where HTTP Debugging Proxies come in handy.

(Firefox users: Don't bother commenting. I can care less what's built into your browser. ;-)