Battery University – great site for all things related to batteries!
Dave Jones’ EEVblog – the mother of all electronic blogs
Andreas Spiess– “The man with the Swiss accent!”
Great Scott Gadgets – Great resource for RF products/projects.
mjlorton – Great resource for multiple technologies
W2aew – Videos on hobby electronics, test & measurement, ham radio, and other stuff.
Voltlog – great video and text log
The Signal Path – Incredibly in depth and technical!
The Gansle Group– “The” resource for embedded development!