I don't think I've ever read a book and thought the character was just like me. I love it when I get that "I do that too!" feeling from a book – Bridget Jones's Diary was brilliant for that – and I know I used to think I was quite like Darrell from Malory Towers, but beyond that I'm not really sure.
I do, however, remember a friend telling me that she read Human Croquet by Kate Atkinson and it sounded just like me. I don't think it was that the character was like me, I think she thought it sounded like I'd written it. I'm assuming that's an enormous compliment since it's, you know, Kate Atkinson, but I still haven't been able to bring myself to read it.