Well, with White's revised version of the Alcubierre drive, I see `warp` technology happening within the next three decades, maybe sooner. It still requires a tremendous ammount of energy, but I think it's nothing an extensive nuclear powerplant can not handle. There's still Star Trek's option of powering it per Antimatter, but that's highly risky.
Perhaps though, an antimatter powerplant build on the moon, or in high orbit would suffice in creating fuel in a safer way.

Now for building the bloody thing, there's always that proposed Japanese space-elevator; once finished, it would reduce further costs a lot.