In his most recent article for Space.com's SETI feature, Seth suggests that, thanks to huge advances in probe technologies vs. modest advances in rocketry, unmanned spaceflight is humanity's best bet for extra-solar exploration in the near future:
"Let's look at some numbers. Von Braun's V-2 rockets crossed the English Channel at 1 mile per second. NASA's New Horizons mission to Pluto - the fastest spacecraft ever launched - is headed to this erstwhile planet at 10 miles per second. That's an order-of-magnitude improvement after 70 years.
Now consider one component of our remote sensing capabilities - our ability to "see" what we're exploring. The Mariner 4 spacecraft - the first to snap decent photos of Mars - was fitted with a monochrome TV camera having a resolution of 40 thousand pixels. In the summer of 1965, it sailed by the red planet while imaging craters as small as a few miles across.
Today, the HiRISE camera on NASA's Mars Reconnaissance Orbiter boasts a resolution of 200 million pixels (and shoots in color). It can discern items on the surface as small as a horse.
In other words, in seven decades our rockets sped up by a factor of ten, but in little more than half that time our cameras improved by a factor of five thousand. There's no comparison: probe technology is marching to the beat of a faster drummer."
You can read the whole article here or here. Paul Gilster also wrote a similar piece for Centauri Dreams, which you can read here and a follow up comparing his article to Seth's which you can read here.