Pluto on the viewscreen, Captain.

[Octafish]

11. Data from space is measured in kilo-BITs...

The Data Rate Challenge

A major challenge for the New Horizons mission is the relatively low "downlink" rate at which data can be transmitted to Earth, especially when you compare it to rates now common for high-speed Internet surfers.

During the Jupiter flyby in February 2007, New Horizons sent data home at about 38 kilobits per second (kbps), which is slightly slower than the transmission speed for most computer modems. The average downlink rate after New Horizons passes Pluto (and sends the bulk of its encounter data back to Earth) is approximately 2,000 bits per second, a rate the spacecraft achieves by downlinking with both of its transmitters through NASA's largest antennas. Even then, it will take until late 2016 to bring down all the encounter data stored on the spacecraft's recorders.

Since NASA's Deep Space Network has to track other missions besides New Horizons, the team plans to produce a lossy compressed browse data set that can be sent down more quickly. The browse dataset will be downlinked before the end of 2015; the complete dataset will be downlinked after the browse dataset.

SOURCE: http://pluto.jhuapl.edu/Mission/Spacecraft/Data-Collection.php

T-Husky from somewhere on the Internet adds...

On the 14th July 2015, New Horizons will arrive at Pluto, which will at that point in the relative orbits of both Earth and Pluto around the Sun, be 32.9AU distance from Earth = 4,921,769,945.734km = 4.56 light hours.
Radio waves travel at the speed of light, so therefore it will take 4hrs 33min 10sec for a radio transmission to travel from Pluto to Earth at this time.
At this distance, New Horizons' bandwidth (or rate of transmission) is limited to 1Kbit/s, so the total time it will take for the transmission to complete will depend on the size of the data packet being transmitted.
The size of the data packet cannot be precisely estimated, however a useful baseline might be taken from New Horizons' 2007 flyby of Jupiter, which generated a 36Gbit data set... so if the Pluto flyby generates a similar sized data set, it would take 447days 9hrs 24mins of uninterrupted transmission for the full data set to be received on Earth (plus 4hrs 33mins travel time).
However, that would only be true if New Horizons maintained the same distance from Earth for the entire duration of the data transmission; New Horizons will actually continue to travel further away from the Earth / Sun, so the time for a complete transmission will take significantly longer, both as the signal strength is further weakened, and the time required for the data packets to travel increases with distance.

http://www.reddit.com/r/space/comments/2qi9ti/when_new_horizons_arrives_at_pluto_how_much_time/

PS: It IS truly thrilling science, sharp_stick!