Who do you think are some of the top artists on youtube?

I Stumbled across these 2 artists who are doing well!
One is a producer as well and just started posting videos and the other has been posting videos for a while and keeps improving!

http://www.youtube.com/watch?v=4qF8Iz-T5HQ&feature=g-upl
and
http://www.youtube.com/watch?v=V_bUce0oW4Q

Lemme know what you think and what other artists you're into!