Worth starting a specific thread for, particularly with this article:
New Horizons at Jupiter: Dreams and Reality
We've been working for several years on a plan for making the most of New Horizons' flight past Jupiter. For our prime mission, Jupiter's really just a stepping stone, a gravitational convenience, giving us a boost that shaves a few precious years off our flight time to Pluto. But it's also one of the most amazing neighborhoods in the solar system, a place full of wonders, and although we're the eighth spacecraft to Jupiter, the payload that we're carrying to Pluto is well suited for some unique Jupiter science, too.
Since we started work on this mission in earnest in 2001, we've been aware of how much we stand to learn from a Jupiter flyby, and we've been developing a wish list of observations of the Jupiter system that we'd like to make. Some of these use New Horizons' unique capabilities to fill gaps in our knowledge -- for instance we don't yet have a good handle on the atmospheres of Jupiter's four big "Galilean" moons, and our ultraviolet instrument, Alice, can help with that by watching stars as they pass behind the moons.