My absolute favorite, and I'm not sure if he has been mentioned, is Major Slack.
He prides himself on not doing "blind walkthroughs" (think RadBrad).
He play tests everything and tells you the best, most efficient way to play the game.
He is a little too SkyRim happy but some of his walkthroughs have made the games so much more fun to me (Prey, all Borderlands, Bioshock, SkyRim, Fallout, etc)
Special mention to patologTV who has great 100% type walkthroughs but no commentary (which I miss).
For sheer humor, you can't go wrong with Tyrannicon.