Index: django/db/models/fields/__init__.py
===================================================================
--- django/db/models/fields/__init__.py	(revision 5505)
+++ django/db/models/fields/__init__.py	(working copy)
@@ -300,7 +300,10 @@
         "Returns a list of tuples used as SelectField choices for this field."
         first_choice = include_blank and blank_choice or []
         if self.choices:
-            return first_choice + list(self.choices)
+	    lst = list(self.choices)
+	    if not self.blank or blank_choice[0][0]  in (str(x[0]) for x in lst):
+	        return lst
+            return first_choice + lst
         rel_model = self.rel.to
         if hasattr(self.rel, 'get_related_field'):
             lst = [(getattr(x, self.rel.get_related_field().attname), str(x)) for x in rel_model._default_manager.complex_filter(self.rel.limit_choices_to)]