You can override the system default formats and choose custom date/time formats, so that you can have Ctrl+D insert the string "26-Apr: " for example. Here are the dialogs where you can configure this:
The codes used here are the same as those used in the "Regional and Language Options" control panel applet.
So -- do you like it? Personally, I tend use The Guide as a journal frequently, with each node representing a day's notes. The insert date feature would be quite handy in this case.