Book Elena was a very complex character - on the one hand she was this girl who liked to be in control of things, who looked after herself, who was really a power magnet and men were very quickly attracted to her, yes she was selfish, yes she did not mind using her friends and she was very clear about what she wanted. On the other hand she had a conscience, she would have moments when she realized what a horrible person she had been to her friends and how she used them, she would die for her friends and like book Damon perfectly described her - she does not need to be protected, she should be protected from. But it all worked and that is what made her an interesting character to feel for.
Book Bonnie was never like tv Caroline - not before or after she turned - book Bonnie was such a cute character who seemed very weak on the outside, but actually was very strong on the inside even when she was scared out of her mind. Not to even say how useful her "witch" skills were.