GTK/Gnome users. You can put the following two lines in a file called .gtkrc-2.0 in your home directory and you will get emacs like keybinding support in programs like Firefox. Then you can use Ctrl-U to clear your address bar, Ctrl-A and Ctrl-E to go to the beginning and end of line, etc.
include "/usr/share/themes/Emacs/gtk-2.0-key/gtkrc"
gtk-key-theme-name = "Emacs"
You'll need to change the include line to point at wherever your Emacs/gtk-2.0-key/gtkrc is on your system.
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