First, the honorable mentions:
The entire crew at io9. It's hard to describe io9. We know they come from the future (or at least they claim to), and apparently, the future is filled with extremely strange scientific stories. Losing your sense of taste, manipulating the dreams of rats and brain-eating protists are just a flavor of the oddities you will encounter there. Esther Inglis-Arkell, Robert Gonzalez, Annalee Newitz, Alasdair Wilkins and George Dvorsky in particular keep us intrigued.
Rhett Allain. How much does Darth Vader weigh? Rhett Allain can tell you using a few assumptions, some Star Wars footage, and basic math. Allain's blog, Dot Physics, uses everyday examples to explain classical physics. If only all physics professors were as entertaining as he is.
Maria Konnikova. It's rare to meet a psychologist who is willing to admit that psychology isn't a science. But that's what Maria Konnikova has done. Indeed, psychology is insightful, and experimental psychology can be scientific. However, as a general rule, psychology often falls short of the rigorous standards adopted by the hard sciences. Konnikova not only acknowledges this, but embraces it... making her quite possibly the most honest psychology writer on the Internet.
Matt Soniak. This Mental Floss science blogger covers a myriad of topics, usually answering those pesky questions we harassed our parents with on long road trips: What are eye boogers? How much does a cloud weigh? Can tin foil hats prevent aliens from reading our thoughts? We also enjoyed his foray into science history, explaining how large breasts helped motivate the invention of the stethoscope.
(Image: Trophy via Wikimedia Commons)