For those looking for a single solution to solve the world's problems, this will disappoint. However, for those who understand it is the proper mix and application of multiple sources of fuel which will solve our need for energy, this will really excite you.
President Obama has made it a centerpiece of his work to incent the movement of Class VIII trucks to natural gas. This is absolutely the right call. It is abundant and clean. Further, the technology is much further along than people realize. With the announcement of multiple distribution agreements and the build out of NG fueling stations, this is an idea whose time has come.
The question of CNG (Compressed Natural Gas) or LNG (Liquified Natural Gas) is one of application. Both have a role. Generally speaking CNG is easier to distribute and does not require the cryogenic freezing of LNG (It is liquified by freezing the NG to -260 degrees F - Read more about LNG here). However, LNG does allow your truck to go further. Read: One is probably great for short haul, out and back type of applications (CNG). One is better for over the road (LNG).
One drawback to LNG for those who look at the entire distribution supply chain: LNG has to get to the station via truck. A lot of trucks on the road to distribute LNG. So, while the end truck may be powered by clean LNG you have to ask yourself how it go to your distribution point.
CNG moves in pipelines and is compressed at point of use so this issue above does not apply.
I am personally very excited about these opportunities. We are heading in the right direction for sure thanks to some very daring and exciting people such as T. Boone Pickens and Aubrey Mclendon.