Which one? Clint Barton or Kate Bishop. They're both equally awesome in my opinion, unless you're referring to the movies.
My favorite hero in DC Comics is probably Guy Gardner (Green Lantern) or Aquaman. I like Guy because his storyline in the Red Lanterns line of comics is what introduced me to DC the first time. And I like Aquaman because of how awesome he is in the comics. In many of the TV shows, Aquaman is treated as a bad hero or a very weak one at best. But in the comics he's totally bad ass. I could easily write an essay on how awesome Aquaman really is.
As for Marvel, I like Deadpool and Squirrel Girl. Luke Cage is pretty interesting as well, and Black Panther is up there as well. Deadpool, I like not because of his wacky antics, but because of his depth. Starting from the third volume of Deadpool comics, he's really grown as a character. He has a daughter that he's super protective of, great friends in SHIELD, and the daughter of a demon as his wife. He's grown a lot since his first introduction.
Squirrel Girl is an odd choice, and an equally odd hero, but she's hilarious and one of the most powerful heroes in the Marvel universe. To put this in persepctive, she has defeated Thanos, Dr. Doom, and Galactus (twice). She's also beaten Deadpool to a standstill, and she's just a hilariously adorable character in general. Her comics are definitely worth a read.
Luke Cage and Black Panther I kind of like for the same reason. They're just interesting characters with a lot of backstory. They're the straight men of the Avengers, always taking things in stride and just being total BAs.
There are tons of other heroes I like. Here's a few I can think of off the top of my head: Tim Drake (Red Robin), Harley Quinn, Simon Baz (another Green Lantern), Cassie Cain, Miles Morales (Ultimate Spiderman), and Spider-Gwen to name a few.
I like comics.
