The DVD release of Dr. Horrible's Sing-Along Blog contains a commentary track entitled "Commentary: The Musical". One of the songs in the musical is actually titled "It's All About Me", and consists of small sections sung by each of the extras in the production, explaining how it really is all about them...
There is a song from The Batterys Down in which a Jewish 13-year-old sings about how her bat mitzvah is all about her, so everybody better practically worship her.
The Order of the Stick: Nale, more than anyone, is a firm believer in this trope. What matters most to him isn't necessarily the end result, or the methods used, but that he wins and that the opponent knows he was the one to do it. This contrasts him with his brother Elan, a selfless hero who cares deeply about genre conventions. Their father Tarquin also acts this way, not even understanding why murdering people for the few he cares about would bother them, and whose entire life philosophy can be summed up as "This is my story", taking steps to "correct" anything and anyone that isn't following his "script".
In the Start of Darkness prequel book, when Right-eye and Redcloak are trying to determine why Redcloak wasn't affected by a magical disease, Xykon interupts with a "Well, that's great, but if we can steer the topic back to where it belongs, namely me..."
The Nostalgia Chick pays little attention to any feelings or problems that aren't her own. It's not clear whether she even notices them or just doesn't give a crap.
A number of reviewers on That Guy with the Glasses fit that description as well. The cast commentary for Suburban Knights has them lampshade how selfish and hate-filled their characters all are to each other, although Doug's own commentary calls attention to how they're more like a fucked up but caring family and how Joe still sat down after his Big "NO!".
A great amount of the customers featured on Not Always Right fall into this, as they believe "the customer is always right" means "you must serve me and me alone perfectly".
Precocious: Could definitely be the worldview of most of the kids.
The Twilight Sparkle in the universe of Friendship is Witchcraft is a totally self-absorbed geek who can't comprehend the fact that the world doesn't revolve around her. While the series starts off treating this for (comparatively) lighthearted laughs, Twilight's character descends further and further into Black Comedy as it becomes clear just what a morally-bankrupt monster she really is.
morphE features Billy Thatcher. A chess grandmaster and television star. This obviously means that he is the only one of the kidnapped mages who needs to get back to his regular life. He refuses to care about the plight of the other captives of whom he assumes are idiots and cowards.