iHex - iHex is the premier hex editor and data analysis tool for Mac OS X.
Beyond Compare - Beyond Compare allows you to compare files and folders.
HextEdit - HextEdit is a proficient hex editor and disassembler for Mac.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
PilotEdit - PilotEdit Lite is an advanced text and hex editor that supports opening of files larger than 4GB.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.