-Been really enjoying Trump for Hearthstone content lately, even though I've started playing a lot less lately and am, by no means, a good player.
-Leeandlie (or Amalee) puts out English dub for some anime/gaming songs and recently announced that she's putting out an EP to redo her older SAO works.
-ZAM Official's another that I've been watching for Hearthstone content from SpaceWizard but they've also started putting up previews to games that I want to play in the near future, including Fire Emblem Fates and Bravely Second.
-Phylol for some League of Legends content. I don't watch streamers so this is a nice thing to have, especially with him posting more lately.
-Protatomonster's another League of Legends content creator. He basically shows the top 5 plays per week from high-level games.
-VGOOnline only posts a few videos per year but I really love what they do. They basically make rock orchestral variations on game tracks including Chrono Trigger, Blinded By Light (FFXIII) and Time's Scar (Chrono Cross).
-TheRunawayGuys' channel consists of three Let's Players who play games together and post em with, often, hilarious results. I haven't been watching their recent stuff because I've been so busy but I would if I could.
...clearly I don't have one particular favourite YouTuber.