And along the same lines, I had a huge crush on Robin in Kindergarden, and somhow got that crush mixed up with wanting to be him. One of the very few ‘playful’ things my mother ever did for me was to make me a Robin cape. I was soooooooo disappointed that I couldn’t wear it to school!
Next crush: Peter Tork of the Monkees. Didn’t want to BE him tho! 
I definitely identified with Spock. I thought I was similar to him: logical and unemotional.
When I was younger, though, it was Drake Andrews of The Aquanauts. I can’t remember why, but I liked the show and stopped watching when he left.
I always wanted to be The Professor from Gilligan’s Island. That dude could do anything!
I wanted to be Barbara Cooper, the Valerie Bertinelli character from One Day at a Time. She’s about the same age as me, but in the show she was so pretty, and funny, and had a cool mom and sister.
I wanted to be Apache Chief: smart enough that even Batman defers to him in his area of expertise, and as big and strong as he needs to be – and not because he happened to be from Krypton or whatever, but because he worked for it. (Plus, in a twist on Seanbaby’s quip, it impressed me that as far as I could tell the guy simply was the Apache Chief: it was literally as if, in an emergency, we’d call on the Flash and Green Lantern and, say, the Israeli Prime Minister, who didn’t bother with a mask or a secret identity.
As my username indicates, I always wanted to be Ponch on CHiPs (the late 70s-early 80s show about California Highway Patrol motorcycle cops). We used to have a dog named Ponch, which was already her name before we adopted her. I became a CHiPs fan because of our dog.
Well, there weren’t any good female characters to identify with! I can’t think of a single one that I actually wanted to be (oh, wait, Wonder Woman.). I grew up watching the Dukes of Hazzard and the A-Team and stuff like that, and the girls were always peripheral or dopey. Who would want to be Mallory Keaton?
I liked Mindy on Mork and Mindy, and Wonder Woman. That’s all I can think of.
Except repair a boat.
My “who I’d want to be like when I become an adult” was Thomas Sullivan Magnum.
The guy I wanted to be when I was a kid was Ricardo Tubs, from Miami Vice (sometimes it would jump to being Castillo whenever he went on samurai sprees)
Michael Knight. But then, I’m German, so no big surprise there.
Being a teen/tween in the early 90s, I wanted to be Clarissa Darling. She had friends but wasn’t part of the snobby cliques, and I loved her clothes. (Well, at least at the time.)
Sailor Mars or the pink Power Ranger.
Elizabeth Walton or Laura Ingalls
Yep. Plus he had the sweetest room.
Bret Maverick: good looking, lady killer, fast with a gun, and quick with a quip.
I was an adult when those shows came out, so they don’t qualify. Heck, I didn’t even like the comic Wonder Woman when I was a kid, because she was always getting tied up (and sometimes spanked) and even as a kid, that didn’t appeal to me in a role model. I wanted a strong, smart woman as my role model. There really weren’t any available.
I can’t remember wanting to ‘be’ a kid on a show, but I wanted to live in The Addams Family’s house.
Batman.
I also liked X-Men (the cartoon, so that dates me as young), but didn’t like the female characters much, except for Storm.
I also think I wanted to be Jennifer Love Hewitt from Party of Five. Or maybe I just wanted Scott to be my boyfriend.
I never wanted to ‘be’ Claire Danes when she was in My So-Called Life, but I definitely related.
I wanted to be Wednesday from the Addams Family and live in their house. Plus, cool toys.
Otherwise, I wanted to be Sarah Jane Smith from Doctor Who. She was smart, inquisitive, and pretty. Plus she got to travel with the Doctor. What could be better?
Ash Ketchum from Pallet Town.