I'd like Ctrl-Backspace to delete the current word in vim insert mode. From within xterm I can pull this off via

:inoremap <C-H> <C-W>

but in gnome-terminal I cannot figure out a way to make it happen.

When in vim insert mode, if I type control-v and then press backspace, I get ^H in xterm, and ^? in gnome-terminal. Unfortunately,

:inoremap <C-?> <C-W>

doesn't do the trick in gnome-terminal; control-backspace just erases a single character no matter what.

Regarding ASCII codes:

Gnome-terminal lets you change the backspace character under Edit -> Profile Preferences -> Compatibility. Unfortunately, no option works, as far as I can tell: whatever character I apply to Backspace via the settings, if I try mapping the character itself, like

:inoremap <C-H> <C-W>

then regular backspace and control-backspace both erase an entire word; and if I try mapping control plus that character, like

:inoremap <C-^H> <C-W>

then regular backspace and control-backspace just erase a single character.