The world needs a new source of energy, an unspillable source.

What are the current types of thrust propulsion, how strong is each type of thrust, and in what conditions?

would such thrust be useful? Solid Rocket, Liquid Rocket, Hybrid Fuel rocket, Hall thruster, Electrical thrust, Ion Thrust, Photon Thrust, Magnetic Thrust, Ramrocket, Air breathing rocket, Space breathing rocket, etc etc? How do these work? what else is there?
which are the most useful?
http://answers.yahoo.com/question/index;_ylt=AkvTKiYgOe27drex2bqTYs_sy6IX?qid=20060616171345AA35gwk