It also isn't what range() and xrange() are used for now in 2.x. range()
returns an actual list, hence is limited to sequences that fit in a
reasonable amount of memory, and xrange() doesn't support values greater
than sys.maxint at all (as it uses C ints for its internal storage of
the start, stop and step values).

With itertools.count() available for the unbounded iterator case, I
think making range() mimic its 2.x counterpart as closely as possible
(without the memory inefficiency) will be quite valuable.