See the question and my original answer on StackOverflow

This property is defined in each Visual Studio Project Template

So, for example, the C# Console Application template is located in

\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\ProjectTemplates\CSharp\Windows\1033\ConsoleApplication\consoleapplication.csproj

The csproj is an XML file that you can edit at your will. The build output directory is define like this (for each configuration):

...
<OutputPath>bin\Debug\</OutputPath>
...
<OutputPath>bin\Release\</OutputPath>
...

If you change this file, it will change all your future new C# Console Application projects. You could also write a utility program that list all csproj in \Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\ProjectTemplates and update them accordingly.