Sorata from Sakurasou no Pet na Kanojo.
He is surrounded by people who are way more talented than he is; geniuses who can do amazing things with such ease, but rather than being discouraged by his friends’ talent he is encouraged and inspired by it. I like how Sorata works so hard and always tries his best in order to achieve his dream.
Lately I'm rooting for Johnny Gill (D.Gray-man). It makes me sad to see so many people bash him when he's getting pretty good development in the recent arc. Sure, he's pretty wimpy and naïve, but that's why he balances out Kanda and Allen so well.
For me its Gutts from Berserk because he does not have a prestigous background like Luffy, Ichigo, or Naruto, and is at a severe physical disadvantage against every apostle he faces. He gets by basically through the strength of his will and experience not by absurd powerups. If he was a weak minded person he would have died a long time ago.
1. Guts (Berserk) others have stated the reasons for this.
2. Furuichi (Beelzebub) no one likes women more than him, yet he is the least successful.
3. Tenma (Monster) A mild mannered, gentle physician who becomes a warrior