Reading this thread on Stackoverflow http://stackoverflow.com/questions/5498197/need-a-good-hex-editor-for-linux I wondered how come with so many hex editors in Linux there is not really the best one.
In Windows it is easier - the expensive WinHex or the cheap Hview. Anyway, as to the Linux I always use Vim
to switch to HEx editing mode, and after finishing the edit issuing
back to binary to be able to save the edited file.
Do not save in the HEx editing mode - the file will be saved as ASCII hex representation file, always revert back to binary.