At BUILD Keynote, Microsoft announced Visual Studio 11 Developer Preview and .NET 4.5 Framework. Here are some good resources to start.

Visual Studio 11:

What's New in Visual Studio 11 Developer Preview

http://msdn.microsoft.com/en-us/library/bb386063%28v=VS.110%29.aspx

Download:

http://go.microsoft.com/fwlink/?LinkId=225709

.NET Framework 4.5:

What's New in the .NET Framework 4.5 Developer Preview

http://msdn.microsoft.com/en-us/library/w0x726c2%28v=VS.110%29.aspx

Download:

http://go.microsoft.com/fwlink/?LinkId=225767

ASP.NET 4.5:

What’s New for ASP.NET 4.5

http://msdn.microsoft.com/en-us/library/hh420390(v=VS.110).aspx

All in One White Paper:

http://www.asp.net/vnext/whats-new

ALL in one Developer Preview Details:

http://msdn.microsoft.com/en-us/vstudio/hh127353

Do let us know what new feature you like most?