I've tried out lots of things to get the default date displaying as today but nothing seems to work.

I'm using this:

1.  $(function() {
2.         $( "#datepicker" ).datepicker({
3. dateFormat: "dd.mm.y",
4.                 changeMonth: true,
5.                 changeYear: true,
6. onClose: function(dateText, inst) {
7.                 var validDate = $.datepicker.formatDate( "dd.mm.y",                                  $('#datepicker').datepicker('getDate'));
8.             $('#datepicker').datepicker('setDate', validDate); },
9. defaultDate: null,
10.         });
11.     });

Cheers