Listmania!
C/C++ Books
The  C Programming Language (2nd Edition)The C Programming Language (2nd Edition) by Brian W. Kernighan
Buy new: £19.16 / Used from: £14.60
The manual for C.
C++: How to ProgramC++: How to Program by Harvey M. Deitel
Buy used from: £6.98
Excellent introduction to C++
Numerical Recipes in C++: The Art of Scientific ComputingNumerical Recipes in C++: The Art of Scientific Computing by William H. Press
Buy used from: £35.00
Useful algorithms. Theory a bit heavy and incomprehensible.
Advanced CORBA Programming with C++ (APC)Advanced CORBA Programming with C++ (APC) by Michi Henning
Buy new: £43.69 / Used from: £3.00
Only decent book I've found on CORBA with C++.
The STL Tutorial and Reference Guide: C++ Programming with the Standard Template Library (Professional Computing)The STL Tutorial and Reference Guide: C++ Programming with the Standard Template Library (Professional Computing) by David R. Musser
Buy new: £31.49 / Used from: £7.33
The reference manual for the STL.
The C++ Programming Language, Special EditionThe C++ Programming Language, Special Edition by Bjarne Stroustrup
Buy new: £27.46 / Used from: £22.00
I know some don't like it, but it is the reference manual for C++.
Design patterns : elements of reusable object-oriented softwareDesign patterns : elements of reusable object-oriented software by Erich Gamma
Buy new: £24.66 / Used from: £18.00
A lot of examples in C++. Useful for figuring out what others have done.
Programming with POSIX Threads (Addison-Wesley Professional Computing)Programming with POSIX Threads (Addison-Wesley Professional Computing) by David R. Butenhof
Buy new: £35.04 / Used from: £24.99
Guide to the standard for Threads.