Fun with Gnome 2
These two commands set keybindings for horizonatally and vertically maximizing a window. Most of the time when you maximize, you only need one of the two dimentions to be bigger.
$ gconftool-2 --type string -s \
/apps/metacity/window_keybindings/maximize_vertically \
'<Ctrl><Alt>v'
$ gconftool-2 --type string -s \
/apps/metacity/window_keybindings/maximize_horizontally \
'<Ctrl><Alt>h'