HexEdit is hex editor that is renowned for its intuitive interface and ability to quickly and reliably edit files of any size (over 4Gb).
It has many options like: autofit, hex/decimal addresses, RO/RW, INS/OVR modes, easy font/size selection, mouse-wheel support, drag and drop, print selection (coalescing duplicate lines), margin/line-spacing, print preview, fast (Boyer-Moore) searches/replaces, compares, highlighter, clipboard support (binary, ASCII, EBCDIC, Unicode), bookmarks, window tabs & colour schemes.
It can continuously display over 60 properties in a pinable dialog: including decimal (8/16/32/64 bit values, big- or little-endian, signed/unsigned), IEEE/IBM floats, dates etc. You can also edit properties, eg. change a date. You can see characters as ASCII/ANSI, IBM/OEM (MSDOS), EBCDIC using the char set drop-down list.
Time-saving features include the Find tool (with drop-down history list) that allows quick searches for hex digits or strings, and hex/decimal jump tools. The status bar displays number of occurrences of current search string, distance from the cursor to the "mark", RO/RW, INS/OVR, REC, CAPS etc. The length of the selection is available while selecting or by pressing the SHIFT key.
Advanced features include unlimited file/window undo, background searches, keystroke macros, CRCs, Motorola-S/Intel-hex files. A powerful calculator is included that has many features (16 binary ops, 16 unary ops, memory etc). The calculator allows file manipulation and is tightly integrated with macros making it simple to create and repeat complex operations.
You can completely customize menus, keyboard & toolbars (even edit button images), 7 different context menus, 3 different double-click events, user tools etc. All user-defined keys appear in menus and tooltips.
Version 2.5 adds replace, bookmarks, unlimited recent file list, printing and UI improvements. An advanced template system lets you describe virtually any type of data.