I would like something that allows me to:Inspect all HTTP(S) traffic between my computer and the Internet, including 127.0.0.1Modify incoming or outgoing dataIt would also be nice if it had a scripting subsystem for setting rules and eventsI prefer it be a GUI application.Please do not answer with WireShark.  I am aware of WireShark and I have used it many many times and it's a great app.  I would like something that restricts it's captures to the application layer and HTTP(S) traffic only and ignores the other Internet Protocol Suite layers.  Also, it doesn't have some of the features I listed above.
Can anybody recommend an HTTP debugging proxy?
linux;gnome;http logging;http proxy
Here are a couple:WebScarab: http://www.owasp.org/index.php/OWASP_WebScarab_ProjectBurp http://portswigger.net/proxy/