Tobuscus. Jacksfilms [YGS 50 WOOHOO], whoever it is that's sticking those Hetacrack episodes up there (HeartSoulDivide I think), and Marasy8 for all the awesome piano-ness that I shall never accomplish.
Markiplier. Drunk minecraft is awesome. He's also raised over $40K for cancer and alzheimer's research thru his channel. I think he has the proportionally fastest growing channel, currently gaining over 100K subs a month.
Pewdiepie, Tobuscus, Smosh, Tomska, and Nigahiga. There are a few I watch for music needs, such as Venusblitz for Hetalia character songs, or people I watch for drawing tutorials.
KYR SP33DY and the crew hands down. Bestest people evar. Also Machinima Team Respawn is hilarious. Not normal Respawn, that channel is kinda stupid now.
Well, in my humble opinion, there's a whole lot of good youtubers around now.
I don't have a personal favourite, but I really like the following youtubers (in no particular order):
- PewDiePie (awesomely funny) - Tobuscus (funny and creative - those literals are just like his voice: godly) - Jack from Jacksfilms (awesome sketches and a nice view on messed up grammar) - the guys from "Did You Know Gaming?" - specially JonTron (that rants about old, trashy games) and PeanutButterGamer (who made a great review of awkward japanese games) - The Fine Bros (with their great "react" videos) - MANS1AYER (not sure if that's how we spell his name, but his Skyrim Battles and "Gamer Poop" videos are just hilarious) - TomSka (ASDF movies are plain awesome!) - Smosh
I think that's about it... If I remember more, I post them here XD