Sluggy Freelance's Sam, being a vampire, is way stronger and faster that most of the cast, survives a fight with a major demon and is a Jerk with a Heart of Gold. Unfortunately for him, the only thing he cares about is having sex with as many women as possible, which he is awe-inspiringly terrible at, to the point that his normally extremely potent vampire hypnotism is entirely ineffectual. However, this is the result of Flanderization. In his early appearances, he was far more clever and successful with the ladies until he fixated on Zoe, a girl he couldn't get. Continuous failure made him what he is today.
Although he's nowhere near as competent a ship's captain or military strategist as his second in command, in a recent war games incident where things unexpectedly went hot, he was shown to be a fairly competent tactician in the heat of battle.
The comic's ending gives him a much bigger name, as he successfully halts human evolution and re-writes the future.
Guilded Age The bard in this series, Payet Best, becomes this after he visits a small town and gets hailed as a hero. Lampshaded with the Achievement Unlock: Become a huge Douche.
Exterminatus Now has this in the form of Rogue, who, being the only member of his four man team who isn't idiotic, ax-crazy, or downright repulsive, tends to act in a "better than you" attitude, despite not being that much better than his compatriots.
Erfworld has Stanley The Tool, who is convinced that he's destined to collect all of the Arkentools, despite the fact that he's a bungler with no concept of strategic warfare, diplomacy, or logistics.
He did seem like he was going to be brought down a peg when Wanda became attuned and wound up getting more amazing powers than him, but alas, it was not to be!
Eridan Ampora from Homestuck is an arrogant snob who feels entitled to love and reverence, yet most of his peers view him with opinions ranging from pity (platonic, of course) to outright loathing.
Cronus, if anything, is even worse. He's totally convinced that he is a sensitive, artistic soul who is a musical genius and an all-around selflessly nice guy. In reality it's perfectly plain to everyone that the entire thing is just an act to convince people to sleep with him. While Eridan did actually have a good friend in Feferi even after they stopped being moirails, Cronus is disliked by literally every single other character who has ever come across him. Ouch.
Sam Starfall from Freefall is an example, of a sort. He always plays the big-guy (even going so far as to attempt to introduce himself as an ambassador to the "puny human empire" despite humans being more advanced than his species). The difference is mainly in his goal (to become a famous thief or criminal) rather than his mindset - though Sam does seem aware that he isn't famous yet.
Stand Still, Stay Silent: Due to growing up as a pampered rich kid before hitting a Riches to Rags episode, Emil grew up thinking he excelled at all his chosen subjects, only to have his grades drop the second he entered the public education system. He however interprets this as the school system having it in for him, and hopes to prove himself in the army to show the world that he actually is as good as he thinks he is. When it comes to his army job, he does have some talent, but lacks experience (he joined later than most due to initially having a long schooling period by that world's standards) and, most likely given the above, the right attitude to go up the ranks.