My number one favourite youtuber is Pewdiepie, he uploads about 2-3 videos a day, and always makes me laugh, he also recently reached the 2 million subscribers mark 2 weeks ago and he already gathered over 400000 since then.
http://www.youtube.com/user/PewDiePie?feature=g-all-u
I also like the ERB channel:
http://www.youtube.com/user/ERB?feature=g-user-lik
And Gopher, who does the official nexus modding channel and keeps me informed about mods.
I also watch Nerdcubed, Criken and Robbaz.
Other ones not mentioned:
Rhett and Link - You should know who these guys are already.
WheezyWaiter - Vlogger
Zefrank - Godamned amazing guy. Watch him now.
Angry Joe Show - Lots of good game reviews
The Asdfs - A really funny group of guys who play games, if you like Criken you will like them. There are 4 channels they upload on from 4 of the main guys. Search for the channels Bedbanana, Burritobrian, MrCatbutts, and Dokudokus
FreddieW, Warialasky and Corridor Digital
GoBroPros - (Guys who made Skyrim 2012, they've made some other stuff as well as the new ones. They are working on a new one right now as well)
HISHE or How it Should Have Ended - Movie parody kinda stuff.
Julian Smith, Mystery Guitarman, Lore in a Minute, My Drunk Kitchen, Nqtv (Remi Gaillard), OMFGCata, Total Biscuit, Seananners, Swoozie, The Anvil Stew, The Slow-mo guys, The Indie Machines, Vat19, Vsauce1/2, Some Select Yogscast stuff mostly from the side channels.
That's the best of my subscriptions, I highly reccomend all of them.
Trendkill, Captainsparklez, AllShamNoWow, Two Best Friends and the Madbaggamer are my favorite lets players. Angry Joe and AVGN are my favorite game reviewers. And the Nostalgia Critic/Doug Walker is my favorite movie reviewer. I have a lot of favorites. *Sigh* And I should probably mention my friends channel, the Bronaughts, they do comedy skits.