Looking at the brightest and the best nano craft, this one is endorsed by Stephen Hawking. It is the best, most realistic method of interstellar travel. The crafts themselves cost very little to make and you can launch hundreds of craft for the price of the initial cost. It scales like no other spacecraft, ever. You could have craft go to our close neighboring solar systems and report back within our lifetime. To me it is not a question of, if we can do this, it is a question of how long will it take to convince space programs around the world to put money into it.
In the end I will leave you with the words of Carl Sagan