My favorite WAS Steamtrain cause I enjoyed Dan and Ross and their Steam-game love. However since that series seems to have evapourated, I've gone with Gamegrumps agains to follow Dan (Erin is ok, but its Dan who I love
).
I watch Jacksepticeye on occasion, and Markiplier even less than him, cause I find them to be more "shout-entertainment" then the improvisational comedy the Grumps offer.
That said, like others have said, the best thing to do is do games you enjoy. Or at the least game you THINK you will enjoy. You won't please the world as everyone has different opinions on everything. Instead, do what you enjoy and let the audience who likes what you do find you. Don't please the world, but offer something to a group who enjoy what you can provide them