PewDiePie and TotalBiscuit are still two of my favourite channels on Youtube. The really good videos help me pick a game to buy, help me play the game in a certain way, help me enjoy the game in a different way (playing games makes me enjoy the gameplay, but watching someone else play it lets me see stuff I don't see when I'm playing them).
Bad ones, however, like 12 year olds with horrible microphones and a godawful voice repeating lines from reviews and articles, those put me off, big time. I usually prefer people to just shush when they're making a walkthrough, I can see what you're doing plainly enough.