It does not take many hours of editing binary files with a basic hex editor for you to ask yourself the question, is there a better tool? So with that question in mind, I went looking and after a few hours found a great tool for Mac OSX, it is called "Synalyze It Pro" from http://synalysis.net/
Now there are a lot of really neat features, which you can view on the App Store or at the author's web site. But the one I will call out is the ability to write custom grammars for the binary files you work with and color code them based on what they are.
Now I work with a lot of PCAP files, and this tool has proven to be very help. I am going to share the grammar file I wrote called libpcap.grammar with a GPLv3 license.
Here is a screen shot of my grammar file working on a PCAP file.