I would be voting for Warp Drive technology so we can go somewhere when we ultimately kill off our own planet.
The problem with warp drive is you can't just use it on its own. There's associated tech that goes with it, like deflectors, inertial dampeners, artificial gravity. You decide to zip off at warp speed without those you'd be liquefied.
I'm more interested in transporter technology. We could send unmanned probes to Mars, Titan, Europa etc. to set up pads, with a few relay beacons along the way.