Windows 8 Support

1. Support for Windows Runtime (WinRT)
2. .Net Profile for Metro -Style apps
3. Improved support for sharing DLLs between .NET profiles

ASP.Net
General

1. Built-in providers now natively support SQL Azure
2. Support for implementing WebSocket receivers.
3. Built-In Javascript + CSS combining and minification
4. Asynchrounous pipeline support (Response, Request, HttpHandlers)
5. Performaance Improvements : Multicore JIT, 35% faster startup, memory optimizations, assembly sharing between sites, pre-fetch support
6. Request Validation improvements:AntiXSS built-in, validation usable per field.

ASP.NET Web Pages 2

1. New site templates
2. Versatile validation support
3. Support for OAuth and OpenID
4. Built-in map embedding tools; supports Google, Bing and others

Web Forms

1. Strongly typed data binding
2. MVC-like support for Models
3. HTML encoded binding expressions

HTML 5 Support

1. Control support for new semantic
2. Multifile support for FileUpload control
3. Validator and UpdatePanel now supports new HTML5 elements

Tooling

1. IntelliSense improvements
2. More Javascript Support
3. IIS Express used by default
4. New templates and snippets for HTML5

ASP.Net MVC 4

1. Async controllers
2. Built-in mobile templates + Jquery.Mobile support
3. Alternate views(e.g.print version, mobile site)
4. Support for Receipes: intelligent codegen.

Windows Presentation Foundation

1. Built-in Ribbon controls
2. Databinding Improvements
3. Ability to add breakpoints to databindings
4. Data Source change aware views (Liove Shaping)
5. Validation Improvements
6. Improved legacy UI integration
7. Dispatcher improvements
8. Speed-up of large data sets

Windows Communication Foundation

1. Support for UDP multicast channels
2. TCP channels now work with partial trust
3. Asynchronous operations
4. Streaming improvements
5. Simplified configuration
6. Can now generate service stubs from WSDL
7. WebSocket Support

Windows Workflow Foundation

1. C# expressions
2. State Machine workflows back!
3. Workflow Versioning
4. Code-first activity design
5. Faster Execution
6. Designer usability improvements

MEF 2.0 (Managed Extensibility Framework)

1. Debugging improvements
2. Support for explicit bindings between objects
3. Support for binding POCOs:no more attribute requirements

ADO.NET
General

1. Sparse columns support improved (SQL Server)
2. Passwords are now stored encypted
3. Asynchronous operations
4. SQL Express LocalDB : New light version of SQL Express for developer use. Supported in .NET 4.5, separate patch for 4.0 will be released.

SQL SERVER 2012 ("Denali") Support

1. High Availability support on connection string level
2. Fast failover across multiple subnets
3. Support for new spatial data types(ploygons, arcs etc.)

Entity Framework 4.5

1. Enumeration support
2. Migrations for schema changes
3. Designer improvements
4. Table-valued function support
5. Spatial datatype support
6. Multi-result sproc support
7. Multiple diagrams per model
8. Code-first support
9. Auto-comipled LINQ queries

Base Class Library

1. Usability improved for WeakReferences and Streams
2. Key interfaces now have async versions
3. New ArraySegment and ReadOnlyDictionary classes
4. Support for CLR objects over 2GB IN size
5. Resource file management performance improved
6. Unicode support for consile applications

C# 5.0

1. Support fora async programming: async and await keywords
2. Methods can access call site info as parameters(CallerInfo)

Visual Basic 11

1. Iterator implementations
2. Async ja Await equal to c#
3. Global Keyword for namespace handling
4. Call Hierarchy view available

Visual C++ 11

1. C++11 standard support improved
2. Auto-vectorization and parallelization of loops
3. Support for controlling GPU-driven processing (C++ AMP)

What else?

1. VS 11 with support for .NET 4.5 & Windows 8
2. Roslyn -Is in CTP, Which enables interesting scenarios for integrating the C#/VB compilers to your own apps. Expected to ship post 4.5.

The features may vary in the actual release but most them will be available for sure. Will keep you updated.

Happy Coding