Books that every physicist should read Inspired by How should a physics student study mathematics? and in the same vein as Best books for mathematical background?, although in a more general fashion, I'd like to know if anyone is interested in doing a list of the books 'par excellence' for a physicist.
In spite of the frivolous nature of this post, I think it can be a valuable resource.
For example:

Course of Theoretical Physics - L.D. Landau, E.M. Lifshitz.
Mathematical Methods of Physics - Mathews, Walker. Very nice chapter on complex variables and evaluation of integrals, presenting must-know tricks to solve non-trivial problems. Also contains an introduction to groups and group representations with physical applications.
Mathematics of Classical and Quantum Physics - Byron and Fuller.
Topics in Algebra - I. N. Herstein. Extremely well written, introduce basic concepts in groups, rings, vector spaces, fields and linear transformations. Concepts are motivated and a nice set of problems accompany each chapter (some of them quite challenging).
Partial Differential Equations in Physics - Arnold Sommerfeld. Although a bit dated, very clear explanations. First chapter on Fourier Series is enlightening. The ratio interesting information/page is extremely large. Contains discussions on types of differential equations, integral equations, boundary value problems, special functions and eigenfunctions.

 A: Roger Penrose: The Road to Reality: A Complete Guide to the Laws of the Universe, before they start studying. If that doesn't discourage you you're up to the task.
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*The Principles of Quantum Mechanics by P A M Dirac

*Newton's Principia for the Common Reader by S Chandrasekhar
A: "Quantum field Theory in a Nutshell" by A. Zee is an excellent introduction to the Quantum Field Theory. Zee focuses on physics of main concepts behind QFT and omits trivial mathematical details. His approach is to consider the simplest example possible and then discuss the generalizations. I find it very useful and definitely wish I knew this book as an undergraduate. And the author's approach has the best traits of Feynman's books.
A: There are many books which are very beneficial for every physicist, and it is difficult to judge which ones really make up the must-read list. But in any case the top books in that list, in my opinion, should be not technical ones but the two autobiographic books by Feynman: "Surely, you are joking Mr. Feynman" and "What do you care what other people think". These books are about how a physicist sees the world and how much he enjoys seeing it from that perspective.
A: Gerard t'Hooft has a website with a course in theoretical physics which is comprehensive.
It looks good, but I have only scanned it:
http://www.phys.uu.nl/~thooft/theorist.html
A: A few books not mentioned come to mind:
Feynman, Lectures on Gravitation
Feynman, The Character of Physical Law
Geroch, Mathematical Physics
Geroch Relativity A to B
Susskind, An Introduction to Black Holes, Information and the String Theory Revolution
A: There is a lot of good books in CM, QM, EM... but what every physicist should read, undoubtly, are The Feynman Lectures on Physics. 
A: Paul Dirac - Principles of Quantum mechanics
Robert Griffiths - Consistent Quantum Theory
A. Zee - Quantum Field Theory in a Nutshell
V. Mukhanov - Physical Foundations of Cosmology
A: What is life? E. Schrodinger
The origin of life. F. Dyson
How nature works. P. Bak
Because physics is not only particle physics.
And the trilogy of Weinberg, that with the Landau course forms the holy bible of theoretical physicist. 
A: "Récoltes et Semailles" by Alexander Grothendieck, however it's not for a physicist, but for a scientist in general. I've read it at roughly the same time as "Surely, you are joking Mr. Feynman" and I appreciate RS much more.
I think that book is just invaluable. It is translated in English somewhere and around 25% in Russian, which I read. Though formally per Grothendieck's will all his works shouldn't be distributed, there is little trouble to get them.
I'm not so sure there are books on physics topics itself that can be recommended for everyone. It greatly depends on the interests and the level of the reader.
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*Nonlinear Optics - Robert Boyd

*Photons-Atom Interactions - Cohen Tannoudji

*Photons - Cohen Tannoudji

*Classical Field Theory - A.O Barout (Dover book)

*Problems in General Physics -I.E Irodov (Undergrad/Highschool problem sets)

*Classical Field Thory - Jan Rezwuzki (extremely rare!, Polish academy of sciences)

*Abstract Algebra -Charles Pinter (Dover Book)

*Topology - Mendelson (Dover Book)

*Foundations of Mechanics- Marsden (Very Advanced)

A: I think everyone needs to read Feynman's QED: The Strange Theory of Light and Matter. While there are many great books on QFT, this one shows you the inner workings of the microscopic world like none other. It also gets bonus points for being accessible to basically everyone.
A: One formative book for me was Ed Purcell's Electricity and Magnetism.  Purcell was my early education in thinking like a physicist.  It introduced me to thought experiments, simple models, and the usefulness of new mathematical tools.  It's mathematically very clear, and physically insightful.  The problems are extremely rich.  It manages a huge deal of physics without much unnecessary computation.  When I post replies to physics questions on this board, I sometimes wonder how Purcell would handle it - setting out the physical principles first, carrying out the calculations as clearly and succinctly as possible, and using physical insight for shortcuts and simplifications.  I doubt I will ever live up to his model, though.
My entire freshman class read Purcell during second quarter.  In conversation later, I heard over and over from people that after reading chapter 5, "The Fields Of Moving Charges", they were so awestruck by this 25-page illustrated introduction to relativistic E&M that when they finished, they stared at the wall for about ten minutes, then read the entire thing over again.
Also from the Berkeley physics series, Frank Crawford's Waves is charming, delving into many interesting wave phenomena with very nice explanations.
James Nearing's free book, Mathematical Methods for Physics on undergraduate math methods deserves more attention that it gets.  It's clear, insightful, and packed with good problems.
A: The Old Man and the Sea
by Ernest Hemingway
It is terribly important to recognize that stupendous effort does not always result in substantial gain.
A: Matter and Motion by James C. Maxwell. Dover sells it cheap.  
A: It's not quite as "hard" a read as some of the others on this list, but I thought that Brian Greene's The Elegant Universe offered an enlightening overview of the motivation behind and basic theoretical concepts of string theory (as well as its links to earlier physical theories) up to the late 1990s.
Ditto also on the Feynman Lectures.
A: DIVERGENT SERIES by G.H Hardy .. it is a bit old fashioned but very interesting
A: The variational principles of Mechanics, by Cornelius Lanczos 1. Some light in the often obscure treatment of variational calculus applied to classical mechanics. 
A: Studies in Modern Algebra - edited by A.A. Albert.  (MAA)
A: The Fractal Geometry of Nature, by Benoit Mandelbrot. This is the book that launched a thousand subfields, and nothing in it requires any advanced knowledge, only a fertile imagination.
A: The Six Core Theories of Modern Physics by Charles F. Stevens  has nice brief summaries of modern physics and a good summary of the basic mathematics including a section on functional integrals that is very clear.   
A: I can't believe Fearful Symmetry by A.Zee hasnt been mentioned here uet. Its a popular physics book but it really captures how beautiful and profound symmetries pop out from our physical models and give us glimpses of "the book" presumably written by god.
A: His Dark Materials Series by Philip Pullman. 
Like The Old Man in the Sea it's a novel series, not a hard science book. But perspective is important, and every physicist should definitely take the time to read it through.
A: I recommend Analysis Vol I and Vol II by Terence Tao.
Although it is a book on real analysis but the book is very much different from rest of the books out there. Also, Tao is one of the finest minds of the century and it is important for a student of physics to have a good understanding of the stuff underlying most of the mathematics that we dabble in. Apart from the philosophical satisfaction (in Tao's own words), it helps the reader from not getting into trouble by applying rules without knowing how they came about or what are the limits of their applicability. 
