Bokken
Bokken is a GUI for the Pyew and Radare projects so it offers almost all the same features that Pyew has and and some of the Radare's ones. It's intended to be a basic disassembler, mainly, to analyze malware and vulnerabilities. Currently Bokken is neither an hexadecimal editor nor a full featured disassembler YET, so it should not be used for deep code analysis or to try to modify files with it.