Cygnus Hex Editor 2.50   
by SoftCircuits   

This is the fastest and easiest hex editor available anywhere! Features include tabbed MDI interface, multi-level undo & redo, extensive drag & drop support, Data Inspector allows you to view and edit data using natural data types and structures, support for powerful user-writable plug-ins, blazing fast and flexible search, search and replace, file compare, delete and insert characters as easily as you can in a word processor, edit files up to available virtual memory (up to 2GB), import/export operations, checksum calculations, and many more powerful features.