My only exposure to PewDiePie is from that Retsupurae video, which was enough to completely put me off the both of them. As for Let's Player's I do like, I'm fond of Spoony, Yahtzee/Gabe and Game Grumps. I think it's also worth qualifying this by conceding that I don't really know of many other LP'ers and I only ever watch these things for the shits and giggles, if they have some interesting insights then that's a bonus but I'd generally rather watch a 10 minute review or whatever when it comes to analysis.