The IEEE Spectrum magazine has a good Q&A looking back at the first 50 years in space with Sir Arthur C. Clarke including the following on the Space Elevator.

SPECTRUM: You have lived to see one of your key ideas—geosynchronous satellites—come to fruition. Another idea of yours—the Space Elevator—is coming closer to reality. Do you have any further thoughts on the Space Elevator?

CLARKE: I am very encouraged by the widespread acceptance of the Space Elevator, which can make space transport cheap and affordable to ordinary people. This concept, which I popularised in The Fountains of Paradise (1978), is now taken very seriously, with space agencies and entrepreneurs investing money and effort in developing prototypes. A dozen of these parties competed for the NASA-sponsored, US $150 000 X Prize Cup which took place in October 2006 at the Las Cruces International Airport, New Mexico.

What makes the Space Elevator such an attractive idea is its cost-effectiveness. A ticket to orbit now costs tens of millions of dollars (as the millionaire space tourists have paid). But the actual energy required, if you purchased it from your friendly local utility, would only add about hundred dollars to your electricity bill. And a round-trip would cost only about one tenth of that, as most of the energy could be recovered on the way back!

Once it is built, the Space Elevator could be used to lift payloads, passengers, pre-fabricated components of spacecraft, as well as rocket fuel up to Earth orbit. In this way, more than 90 per cent of the energy needed for the exploration of the Solar System could be provided by Earth-based energy sources. When the Space Elevator becomes a reality in the coming decades, the most expensive components of orbital travel will be in-flight movies and catering.