TotalBiscuit - he's intelligent, reasonable guy with a style of humor that really fits my taste, ability to separate his personal opinions from the more objective ones, and present both in balanced manner, make it clear which is which, and ability to analyse gameplay mechanics and their effects in a very nice and clear way. If I ever finish making my game, it is my dream for him to do WTF is... of it, despite me knowing that he, personally, is going to hate it.
jefmajor - he's smart, despite him constantly claiming he's not and playing "the dumb guy" in a way, just for the fun of it, he's got awesomely juvenile humour, and loves "derping around" in games (i also believe he kind of invented the term), but at the same time, he knows how to really appreciate a game when it's worth of being appreciated, and is capable of story and symbolic analysis and interpretation better than mine - prior to watching his AC lp's I had no idea about the depth of the story despite finishing the game already. He mixes "the deep stuff" with "the derp stuff" in exactly the right amount for me, knows when to talk and when to shut up, and generally is probably the best LPer in my knowledge. On top of that, his choice of games is great, and usually a little different from the rest of the crowd.
vsauce - concentrate of fascinating tidbits of useless but inspiring and thought-provoking facts with a drop of entertainment, asks the most ridiculous and obvious questions with the most surprising and interesting answers. To me, his videos are kind of a "framework" of what edu-tainment should be and how should it be done.
minutephysics - I feel like I learned more from this guy than from all the physics classes in high school. I love his style of dumping relatively big amount of information on the viewer in a short time, I feel like it all connects together in my brain almost automatically thanks to that, as opposed to standard way of explaining, when I'm bored at every corner, because I have to wait for another piece of the puzzle while it is explained in a painfully slow way how the piece just presented fits to the bigger picture, which I already figured out by myself. Generally, I love how he doesn't assume the viewer is stupid.