"Youtube" comedian? I think you mean "stand up" comedian, lol.
Youtube is just a place where their videos can be uploaded... like MySpace, or Google.
My favorite comedians are Jeff Dunham and Stephen Lynch.
Jeff Dunham is a brilliant and hilarious ventriloquist.
And Stephen Lynch... well... I can't bring myself to really recommend him here... he can be very sacriligous and is often fairly vulgar... but he is such through song... yeah... he's not a regular stand up, he's a singer who writes crazy funny and demented songs. But yeah, not everyone's cup of postam (I was going to say tea, but y'know... the word of wisdon and all