Holden Caulfield from The Catcher in the Rye, is the first one to come to mind. And who really wants to admit to relating to Holden? However, the first time I read The Catcher in the Rye, he reminded me of myself and my brother. We both tend to think people are fake and I'm slightly anti-social.
Hermione Granger from (do I have to say it) Harry Potter. Now growing up I never really thought that Hermione reminded me of myself for a long time, however, I had had a few friends who said I was very much like her. Not when it came to school necessarily, I was never one to really care about my grades. It wasn't just that I was smart (after all I hung out with a smart group of kids, and I know I wasn't the smartest). No it was other things like, I'm bossy, and loyal, and to be honest it's really hard to get any sort of control of my hair.
Lena Kaligaris from The Sisterhood of the Traveling pants. There are two main reasons why Lena reminds me of myself. The first is when people tell Lena she's pretty but she doesn't believe it. Not to toot my own horn, but I know I'm cute, however, I don't think I'm as pretty as people tell me I am. The second, is the connection with her grandfather. How even though they couldn't really talk to one another, in a way he was her soul mate, and I often felt that way about my grandfather.
Effie Kaligaris from The Sisterhood of the Traveling Pants. I don't have any sisters, so I know my brother would be angry to know that I would compare him to Effie. I have always saw Effie as bratty, which to be frank, my brother is bratty. He would also take my magical pants from me if I had a pair and made him mad.
Sophie Hatter/Pendragon from Howl's Moving Castle and it's sequels. Sophie is honest and very straight to the point. I like to think that I'm like that. She's also rather bossy, which I'm told I'm like that.
Morwen from the Enchanted Forest Chronicles. Other than being short and wears glasses, Morwen reminds me of myself for a different reason. She does things the way she wants to do them. She doesn't stick to stereotypes or cares how people sees her. Those are the reasons she reminds me of myself.
The Weasley twins from Harry Potter. Let me redeem my brother who I've compared to both Holden and Effie. He and my youngest brother remind me of the twins. My brothers when they get together... are rather dangerous. They're always up to something. They come up with rather sick and weird things to do/make to amuse themselves. The fact that they're border line mean sometimes makes me think I should say Sirius and James instead.
Dairine Callahan from the Young Wizards series. I have a cousin who reminds me of Dair, not that she's smart (she's street smart anyway, not book smart like Dair), but that she's always trying to be better at things than her older cousins. She kind of falls in the middle of all us cousins so maybe it's just a middle child sort of syndrome going on.
Vivenna from Warbreaker. I'm the oldest of three, and growing up I always felt responsible for siblings. There also were a number of times when I was suppose to do something but my siblings got in the way (they wanted to do it to, they got my parents to do something else, my parents just simply changed their minds because of my brothers). And I... felt kind of useless sometimes, and there were times when I tried to make myself less useless, which is probably why Vivenna reminded me of myself.
And I think that's it, I know there's been a number of books that have characters that remind me people I know/myself, but for some reason I can't think of more, I'm surprised I was able to think of nine.