I created a new Blank Solution in Visual Studio 2010, then I did an Add New Project, and the Solution node no longer shows in the Solution Explorer.
Further, when I try
You need to show the solution as follows:
The "Solution solution-name (n projects)" will now show, and you can highlight that node to Add New Project from there.
Trivial Update: My VS 2010 is SP1Rel, and I am on Win7 Enterprise SP 1: