None of them are really indispensible. Map and filter cab be replaced with list comprehensions. reduce is redundant except when multiplying a series; there's a sum function for a reason. Lambda looks cleaner in some cases, but you don't gain any functionality.
What really struck me, though, is the last line of the abstract: "I expect tons of disagreement in the feedback, all from ex-Lisp-or-Scheme folks. :-)" Guido wrote somewhere that the original map, filter, and reduce came from a lisp hacker who missed them. -- http://mail.python.org/mailman/listinfo/python-list
