Wiring for 120 now with 240 option later?
Run all four wires

Run a /3 cable (hot, hot, neutral, ground) to the receptacle location.  For 110, you cap off a hot, and use the other hot, the neutral, and the ground for the receptacle.  For 220, you can cap off the neutral and have 2 hots and a ground for a NEMA 6.  If you want 110 &amp; 220 together at some point, you can then land all four wires on a NEMA 14.

I'd run this circuit using 6/3 by the way -- that allows you to have anything up to a NEMA 14-50 there with an appropriate breaker to match.