From a permaculture (sustainable design) viewpoint, Ive been watching the unfolding of the various solutions for the Gulf oil spill. There is one that stands out above the others for giving real hope and being perhaps the most ethical solution both environmentally and economically: microbes.
Microbes are natures way of balancing the ecosystem and cleaning up toxins in it. There are microbes that eat just about any substance, even heavy metals (they neutralize them, making them unassimilable in living tissues). Naturally occurring microbes in the ocean and on the shoreline will eventually eat the oil, break it down, and neutralize most of the toxins. They bind or transform harmful toxins to inert or even edible ingredients. When they have eaten all the oil, they die off, start sinking to the bottom of the ocean, and the sea returns to its former balanced state. This has happened at the Exxon Valdez site and every other oil spill, on its own. But it takes time, especially when there is so very much oil suddenly appearing in the system.