Add date to a cell with a click...Easy one...

Hi,
I am trying to get a formula setup so when you click on a cell in excel it automatically enters the date. I am using the formula below which works however, I only want it to work on certain cells, ie. A1:A30, A35:A40, C15:C20 etc. Can anyone help me with my very limited VBA Skills. Formula is as follows:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Address = ActiveCell.Address Then
Target = Format(Now, "dd/mm/yyyy")
End If
End Sub.

Thanks a bunch