The RTM version of Visual Studio 2015 is being released today. For developers, I think this will be a huge change as they are looking more towards cross development on other platforms with VS then strictly using it to develop for Windows platforms.
The .NET Framework 4.6 will be released as well today. Mobile development is being expanded to include IOS, Android and Windows platforms. Game development has been expanded to include tools for targeting Unity, Unreal and other platforms. The Roslyn compiler is being released for use with C# and VB.
For anyone interested there will be a Final Release Event at 8:30am PDT