There's also the classic warp drive. I'm not sure that it's possible, but unless we come up with a way to extract energy from spacetime itself, I don't think we'll ever manage intergalactic travel. Hah, now that I think about it, if we ever start testing experimental builds for such machines, I'd like to have some legislation mandating that they're only turned on ~10 light years away from humans and with a trajectory that takes them out of the galaxy.
Well DUH the first thing you do is develop a Kardashev (II) civilization and methods for synthesizing exotic matter and then you go out and scoop about for micro-wormholes and then you send one end out where you need it to be and then you dump a black hole's worth of energy into both sides and then you just walk right through it. And then it doesn't matter how much reaction mass that fucker Tsiolkovsky thinks you need to get up to speed because you're already sitting on a purple beach under a Vegan sun sipping Romulan Ale mai thais. I may or may not have sold this screenplay.