sub build_list {
   my ($arg1, arg2, ...) = @_;
   my @list = ();
   ...
   if (something) {
      return @list;
   } else {
      return ();
   }
}
[download]

This to me _reads_ clearly that an empty list is being returned by a function that operates on lists.

Well, if that sub is actually set up so that @list only gets things pushed into it when "something" is true, then you don't need the two different return conditions -- that is:

sub build_list {
    ...
    my @list = ();

    if ( something ) {
       push @list, $whatever, ...;
    }

    return @list;  # list could still be empty at this point
}
[download]

and when @list is empty, that return statement is exactly equivalent to "return ();" -- to me, this reads even more clearly.