"The 16 Best Science Visualizations of 2011" is an article on Wired Science that has some great images that can be used to get students engaged and excited about science.
The visualizations include mouse eye cells, toxic barbs on a cucumber's skin, self-assembling energy storage and more.
These were selected by the judges based on visual impact, originality and clarity. There are photographs, illustrations, infographics, videos and interactive video games.
You can find even more of them at the contest site: http://www.sciencemag.org/site/special/vis2011/
These images are fascinating and are a great way to get students excited and engaged about science.