* The Pragmatic Programmer
* Coders at Work
* Cocoa Programming for Mac OS X
The Pragmatic Programmer is quite old (published 1999). It provides a lot of useful (generalised) information on how to build a scalable, useable and easy-to-maintain application. The small handout that comes in the back of the book is also a great reference to keep next to your desk!
Coders at Work takes a slightly different approach. Odds are you've heard about it from other users of HN, but in short: It's a selection of interviews with some of the most accomplished programmers around; Knuth, Simon Peyton Jones etc. I'd still recommend this book, but I would probably cut out around 15% of it.
C++ was never given enough time at my University (it was a Java school) and so I wasn't too tied to it when starting out with Cocoa Programming for Mac OS X. If you can understand basic pointer use in C, then this book will hold your hand through Objective-C and into using Interface Builder and XCode to build native Mac applications. It's not going to teach you how to build iPhone apps, but it will give you the correct core knowledge to go on and do so using the Apple docs should you wish.
I'm currently in the process of reading K&R (The C Programming Language book) and Thinking in Java, both of which are regarded quite highly. Although K&R is definitely seen as THE technical book to read.