I'm going with the show Friends:
Ross: Colin Singleton from An Abundance of Katherines --He has a poor dating history and is very smart yet bitter about not being labeled a genius.
Rachel: Holly Hills from The Diary of a Wimpy Kid series --She's pretty, blonde, artistic, and sweet, but she's also the unattainable girl who doesn't seem to know Greg exists.
Monica: Annabeth Chase from the Percy Jackson series --She's smart, organized, and has a little bit of a problem with pride.
Chandler: Ron Weasley from the Harry Potter series --He's socially awkward, often finds his family embarrassing, and generally has a glass-half-empty attitude.
Phoebe: Susan "Stargirl" Caraway from Stargirl --She's quirky and compassionate, dresses eccentrically, sings random songs while strumming, loves nature, and has an upbeat outlook on life.
Joey: Henry McMillan from The Chronicles of Vladimir Tod --He's loyal, popular, and hungry and he has a way with the ladies.
I think I'll attempt to tackle everyone's favorite musical t.v. show - Glee! (Just a few characters...add more in comments if you want to! Chris helped a bit too.)
Sue: Professor Severus Snape from the Harry Potter series --He's always quick to creatively insult his students, he's super competitive, and he has a trademark outfit.
Will: Professor Remus Lupin from the Harry Potter series --If Sue is Snape, Will is Lupin. He's a kind-hearted mentor to Harry and an excellent teacher.
Quinn: Mimi Force from the Blue Bloods series --She's another rich, popular, gorgeous blonde who starts out as a complete brat but grows into a somewhat selfless leader.
Artie: Isaac from The Fault in Our Stars --He struggles with a disability but manages to stay positive and be a good friend. He's also dealing with a pretty tough break-up.
Puck: Rodrick Heffley from the Diary of a Wimpy Kid series --He's all rock-and-roll and rebellion and no direction in life plus he likes to pull practical jokes.
Rachel: Anne Shirley from Anne of Green Gables --She's an over-dramatic yet driven girl who is dying to get out of her small town.
Kurt: Paul from Boy Meets Boy --He's proud of who he is and doesn't want to change, but still struggles with being openly gay in high school.
Mike: Bo Brewster from Ironman --Bo is a gifted athlete but also has to deal with a controlling father. He's also smitten by a girl who shares his gift.
Brittany: Luna Lovegood from the Harry Potter series --She's quirky, cute, and blonde, and she has crazy, fantastical theories about anything and everything.
Santana: Clove from The Hunger Games --She doesn't take crap from anyone, and she's not afraid to go all "District 2" on you!
Finn: Percy Jackson from the Percy Jackson series --He may not be super book smart, but he's got a big heart and a brave soul, he's a loyal friend, and he's completely adorable. Plus, he's got a thing for one of the most driven girls he knows.