Dunkey, Let's Game It Out, NakeyJakey, Digital Foundry, and Gameranx are the ones I watch most regularly.
The Architect of Games and Razbuten are fun ones if you like video essays, and Keenengraz is great for finding lots of insane free games to play. ThatGuyGlen has some cool, short docu-style videos on the making of indie games that are really well done.
I'm sure I'm forgetting plenty, but those are some of my favorites, for sure.