Ah Youtube, the great timesink of my life! There have been a few of my subscriptions already mentioned, here some others in my dubious list:
HackADay
Joerg Sprave (The slingshot channel).
The Tank museum
The Ben Heck show
Tested
Make
What's inside?: Father and son rip things apart to "See whats inside"!
Evan Kale: Electronics and hacks.
Thang 010106: Animations of mechanical linkages.
Tech MD: Cellphone repairs.
Overclockers UK: PC mods and gear.
Adafruit industries: Popular vendors channel showcasing new products
hakology: Hardware and software hacks and how too's
Sparkfun electronics: Same thing as Adafruit, different company!
jimmydiresta: Artisan maker.
Jerry Rig everything: Cellphone repairs and reviews, making and hacking.
Techdrive: Electronics and tech.
Colin Furze: Looney maker with a deathwish! 70mph mobility scooters, pulsejet go Karts, Toasting knife etc.
Rimstar.org: Making, hacking and electronics.
Afrotechmods: Electronics
andrew mcneil: Lots of wi fi antenna stuff.