With a few exceptions, current code requires that you use 14/3 (or 12/3) wiring for switches in almost all branch circuits. (NEC 404.2(C)).
While basic switches do not use the neutral wire (white), many more complex switches do, and current wiring standards require the availability of the neutral to allow use of such devices without rewiring.
If the switch is being used to control the outlet itself, that is one of the exceptions that does not require a neutral.
Also be sure to use the bare or green ground wire on the switch as well.