Auto-fill the current date if the previous row was empty

Hello,

I have a spreadsheet sorted by dates. Everyday, I enter new data into it. After each day, I leave one row empty before starting the next day. Example:

20.09.12 XXXXX XXXXX XXXXX XXXX
         XXXXX XXXX  XXXXX XX
         XX    XXXXX XX    XXXX

21.09.12 XXX   XXXXX XXX   XXXX
         X     XXXX  XXXX  XXX

22.09.12 XXXX  XX    XXXX  XXXX

So I want excel to always fill in the current date whenever I enter data after one blank row, but obviously the dates shall stay the same - not be updated to the current date whenever I open excel. I am using Excel 2007 and while non vba ideas are preferred, vba is not a problem either!