Ptolemy's Gate question

Initially probably not. But in the end he definitely does.

uumm hmm that he does!
But That is only at the end of the series.
Nathaniel never gave him the level of equality and respect that was given by Ptolemy.

Note- It has been a while since I read the book. However, this question did pop up once I'd finished the book. To me the answer to this is, any human who is self-sacrificial, instead of self-serving is somebody who Bartimaeus likes. After all, almost all magicians in the series, approx. 99.9% are cruel, with the exception of Ptolemy, and Nathaniel (in the end of his life). Thus, Bartimaeus possessed respect for Nathaniel, and the girl (I'm afraid I forgot her name), whom Nathaniel fell in love with, and who traveled to the Other Place. She too gained Bartimaeus' respect.

Yeah. Bartimaeus is like "I like you, then I hate you, then I like you..." towards Nathaniel. I guess they might make up between them in the other worlds.

I always found that he was neutral towards Nathaniel, but there was the occasional fondness/disappointment tinted with sarcasm.

I think throughout most of the series Bartimaeus was disappointed in Nathaniel, especially in Ptolemy's Gate but by the end of the series Nathaniel managed to redeem himself, and prove himself not to be fully corrupted and still have the goodness in him that Bartimaeus first saw in ptolemy.