@b0rk @mjd My memory is that there was a big schism in the physical terminal world about what the 'backspace' key generated. Many terminals had it generate Ctrl-H, but some used DEL; I believe DEC terminals such as the VT-100 were in the DEL camp, and they were very popular. This carried over to Unix workstations, with vendors doing different mappings (eg SGI made their 'backspace' key generate Ctrl-H in a default configuration; DEC used DEL of course).
@b0rk @mjd Today, X on Linux has a 'BackSpace' keysym and a 'Delete' keysym, generated by their respective keyboard keys, but I believe that all terminal emulators map both of them to DEL by default (xterm and gnome-terminal certainly do). Things like browsers tend to make the big BackSpace key delete characters to the left of the cursor (what you expect) and the 'Delete' key delete to the right, which can be a surprise.