I have been a fan of the ieHTTPHeaders (v1.6) application for a couple of years now, it has been my HTTP sniffer of choice and has helped me debug a myriad of issues! I realized today, quite by accident, that there was a significant update late last year.
The two obvious (and maybe only) updates include the ability to filter your results by Content Type and HTTP Status code. This kind of filtering is critical, just go to any content rich website, like nba.com, and you will be inundated with a series of responses that you will probably have to copy to notepad just to complete an effective search.
Download here. This is nice ... very nice!