1. Ducky, California Diaries (Ann M. Martin)
Ducky is a sixteen-year old guy living alone with his older brother while his parents explore Pompeii. A sophomore in high school, Ducky is feeling the strain of growing up as his two childhood best friends move away from him. This is a shame, because Ducky's a great guy. Ducky is cool. He has his own eccentric sense of style, he's fun to be around, and he's always there for his friends -- going out of his way to support them, like the time he drove to Venice to find Sunny after she ran away. He makes his appearance in the series by rescuing a few humiliated freshmen who just escaped dangerous hazing incident, and remains devoted to the welfare of his friends throughout the series -- even stopping a suicide attempt.
2. Dobie Gillis, The Many Loves of Dobie Gillis (Max Shulman)
3. Hermione Granger, Harry Potter series (J.K. Rowling)
Except on days when Ravenclaw battled Gryffindor on the quidditch pitch, I guess.
4. Aximili Esgarrouth Isthill - okay, let's just go with "Ax". Animorphs
Ax: We have twenty-six of your minutes left.
Marco: We're on Earth, Ax. They're everyone's minutes.
Ax: (quite deliberately) We now have twenty-five of your minutes.
Jake: Don't call me prince, Ax.
Ax: Yes, Prince Jake.
5. Sam Yeager, WorldWar/Colonization series, Harry Turtledove
In my experience characters named 'Sam' tend to be everymen, and Sam Yeager surely fits the bill. Readers meet him in the WorldWar series as a minor league baseball player who turned soldier after the outbreak of World War 2. Sam passed his long hours on trains during his ballplaying days reading magazines like Astounding Stories, enjoying authors like Asimov and Lester del Ray. When World War 2 is interrupted by an invasion of spacefaring lizards, Sam's SF-strengthened imagination allows him to work with lizard POWs. He becomes the United States' chief expert and is later sent as an ambassador to the lizard Homeworld when the various nations of Earth begin sending ships out into space. He remained likable throughout the series, especially when he stood up against his own government in ethical protest.
6. Liz Ortecho & Alex Manes, Roswell High
7. Ponyboy Curtis (The Outsiders, S.E. Hinton)
8. Hari Seldon
In the original Foundation series, Hari Seldon is a passionate scientist who wanted to preserve civilization, and his Seldon Plan makes him into a godlike figure for members of the series who lived centuries after him -- they only see him as a holgraphic personage who appears in moments of crisis. The prequel books (Prelude to Foundation, Forward the Foundation) visit Hari in his youth as he develops the field of psychohistory. Seldon is in part based on Asimov, so I can't help but like him.
9. Gordianus the Finder, Roma sub Rosa (Steven Saylor)
10. Klaus & Violet Baudelaire, Series of Unfortunate Events (Daniel Handler)
Okay, I'm not sure which I like more. At first I just thought of Klaus, but a friend was surprised I hadn't picked Violet. And then so was I...so I'm going to cheat. Who can choose between two clever, courageous kids such as these?
I suppose in a pinch I'd choose Klaus, because he's forever reading.
Honorable Mentions: Henry Huggins (Beverly Cleary), the Alden kids (Henry, Jessie, Violet, and Benny) though they're rich and clannish. Harry Potter, though he's got a big chip on his shoulder. M&M from That was Then, This is Now; Johnny from The Outsiders. The Narrator from H.G. Well's various novels.
I enjoy playing The Sims 2, and many of these characters and other characters from their series have their names in my neighborhood. One of my favorite sims is named Hari Seldon, and he used to be the town's immortal god-like mayor. His adopted son is Harry Seldon, who looks suspiciously like Harry Potter. I just borrow names from the rest.