Some new additions to the list:
Adam Welch
Andreas Spiess
Beauty and the Bolt (mostly science, but very well presented)
Ben Heck Hacks
bitluni's lab
Blitz City DIY
Brian Lough
Damien Maguire (some power electronics, but mostly mechanical)
Defpom's Electronics & Repair
Electronoobs
electronupdate
Emily's Electric Oddities
glasslinger (DIY vacuum tubes)
James Allen
Johannes Hubner (lots of motor control stuff)
Kaizer Power Electronics
katkimshow
Marco Reps
mjlorton
MrTesla1337
Robert DuHamel/RSD Academy
xraytonyb