YY-MM-DD hh:mm.ss is sanest, as it matches the order of Numerical significance.
+1 to this. YY-MM-DD is also the best when naming files, as it then is trivial to sort them by date.
The MM-DD-YY system is just america making sure absolutely none of their measurement systems make sense.
The Volatile Chemist - 10-11-2015 at 15:58
My watch has 'YY-MM-DD hh:mm.ss'. I prefer it.
Also, when I first saw this thread, I thought it was talking about dating...
I prefer my dates in nice restaurants.