Science Magazine's Breakthrough of the Year 2008

Science magazine has a special feature about the scientific breakthrough of the year, along with the runners-up.  The top spot is "reprogramming cells" where scientists turned skin cells into stem cells, ready for differentiation into different types of cells (such as neurons and glia!)

The runners-up are: seeing planets of other stars(!), cataloging cancer genes, finding a new type of high-temperature superconductors, understanding how proteins work, a cheap(er) way to split water into hydrogen and oxygen, making embryo movies, finding a link between muscle and brown fat (but not the white fat), calculating the mass of protons from first principles, and a new gene sequencing technology.

If you don't want to register (free) to read the site, you can go to Ars Technica to see a summary.