Totalbiscuit - Great mechanical analysis and meta industry coverage with a solid ethical stance and no bullshit. Fun commentary while playing.
Quill18 - Great gameplay videos and pre release coverage. Often in depth videos likke the recent "mechanics of Pillars of Eternity".
SirTwiggy - Great for survival games. Twitch, not sure about Youtube.
Jesse Cox - Fun gameplay, variety of games.
Dodger / Press Heart to Continue - Fun gameplay, weird games.
Angry Joe - Good in depth reviews, fun gameplay.
Sjin, Sips, Hatfilms, Duncan, Kim from Yogscast.
Many SC2 specific channels on twitch and Youtube.