C/C++

All languages use libraries, so that isn’t really quite a distinguishing feature. However you should probably pay attention to the *quality* of libraries available.
Java and Python have the best general libraries, hands down. C++ is good with QT.

http://olvemaudal.wordpress.com/2008/11/27/c-idioms-by-example/
http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms
http://www2.research.att.com/~bs/bs_faq2.html (bjarne’s style/idioms faq)
http://stackoverflow.com/questions/1759613/what-c-idioms-should-c-programmers-use

- qt smart ptrs:
http://stackoverflow.com/questions/2884202/qt-and-auto-ptr
http://labs.qt.nokia.com/2009/08/25/count-with-me-how-many-smart-pointer-classes-does-qt-have/

PIMPL (pointer to implementation idiom)
http://en.wikipedia.org/wiki/Opaque_pointer
http://www.c2.com/cgi/wiki?PimplIdiom
http://www.gotw.ca/gotw/028.htm (fast pimpl)

RAII
http://en.wikipedia.org/wiki/Resource_Acquisition_Is_Initialization

Patterns:
http://en.wikibooks.org/wiki/C++_Programming/Code/Design_Patterns
http://en.wikipedia.org/wiki/Singleton_pattern
http://en.wikipedia.org/wiki/Observer_pattern
http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern
http://en.wikipedia.org/wiki/Decorator_pattern
http://en.wikipedia.org/wiki/Delegation_pattern
http://en.wikipedia.org/wiki/Factory_method_pattern
http://en.wikipedia.org/wiki/Reactor_pattern

COM:
http://msdn.microsoft.com/en-us/library/ms680573%28v=vs.85%29.aspx
http://en.wikipedia.org/wiki/Component_Object_Model

Look at the syllabi:
Basic

1. Introduction to the STL
• purpose and structure of the STL: containers, algorithms, and iterators
• review: class and function templates
• container classification, characteristics, and content
• iterator classification and behavior
• generic algorithms and iterators
• design of generic algorithms and performance guarantees
• iostream iterators
2. Generic Algorithms
• review: generic algorithms and helper templates
• interaction between algorithms and iterators
• generic algorithm goals, documentation, and design
• sequences, subsequences, and sequence errors
• descriptions of STL algorithms
3. Containers
• properties, insertion and deletion effects, specific functionality
• vectors
• lists
• maps
• containers and exceptions
• choosing an appropriate container
• container adapters
4. Function Objects
• functions and generic algorithms
• function objects and generic algorithms
• algorithm families
• function objects and containers, strict weak ordering
• standard function objects

Advanced:

1. Adapters
• function object adapters
• binders and negaters
• helper tempates and template argument deduction
• pointer to function adapters
• composing new function objects
• designing function object adapters
• container adapters
• priority_queues and heaps
2. Iterator Design
• the iterator base class and iterator traits
• review: class template specialization and partial specialization
• iterators and const_iterators
• accessing iterator information in generic algorithms
• versioning of generic algorithms based on iterator class
• reverse iterators and iterator adapters
• insert iterators, adapters, and helpers
• raw storage iterators, adapters, and helpers
• designing new iterators
3. Container Design
• containers vs. STL containers
• STL container requirements
• design of a simple STL container
• design of a more complex STL container
• containers, iterators, and const_iterators
• basic STL components
4. Allocator Design
• containers and memory management
• allocators and the standard allocator
• allocator portability problems
• container use of allocators
• design of a special-purpose allocator
• allocator hacking techniques