Of course Ericzander of BlackStarChronicles is the best. That guy is awesome and always make the best and most easily accessible tutorials. He explains things so well and I always come out of it being completely satisfied. That dude is awesome. Totally check him out.
http://www.youtube.com/user/blackstarchronicles
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Okay shameless promotion over.
1. Vsauce (I always quote him to make myself sound smarter than I really am.)
2. TommyEdisonXP (really cool. Dude's blind and he does a lot of things that us "normal" people can do. And he can joke about himself. Seriously he's awesome.)
3. Nigahiga (Yeah I know, pick an obvious choice. But I still love this guy and I've been watching his videos even before they blew up #hipsterzander)
4. HowItShouldHaveEnded (Simply hilarious. Usually spot-on.)
5. CinemaSins (Known for doing "Everything wrong with *insert movie*" videos. Awesome.)