Of course the Back To The Future Movie Part 2 popularized this concept.  This particular concept is a bit different than a pure floating board, but cool none the less:

The 25 lb (11 kg) Hoverboard is powered by a 5,000 W motor, which is part of the drive-unit at the center of the wheel. This delivers a top speed limited to 16 mph (26 km/h) and a range of 12 miles (19 km). The board charges at a rate of 1.5 minutes per mile. The sonar detection informs the board’s self-balancing system to keep the board parallel with the ground, while regenerative braking is employed to recover energy and charge the board when going down hills or decelerating.

I am very tempted to try one of these out.  What do you think is it worth it?  Feel free to comment if you think this board will catch on or perhaps a future version.

thanks to gizmag for the great info