I prefer pyGTKeditor over leafpad since it supports syntax highlighting which makes things more readable, it also supports portrait mode which is handy if you just want to view the files, as well as hildon autocomplete. the default language for syntax highlighting can be changed by clicking on the title toolbar and clicking on settings.
from the commandline you can access pygtkeditor in the same way as leafpad.

pygtkeditor /etc/xdg/menus/hildon.menu

then for syntax highlighting choose xml or something similar from default language and this will highlight the tags.. if it doesnt highlight the first time, reopen the file after the language change.