This has got to be the most pointless setting in Visual Studio. I can't imagine why any reasonable person would want to hide the solution. Maybe it is for those "Morts" I keep hearing about who bundle everything into one giant ball of mud project so have no need to know about mundane things such as solutions.
I suppose what gets me most is that I like my right-click. I like to right-click on things and get context sensitive menus. I also normally create a new blank solution then add projects to it. The solution disappear when the number of projects equals one. When there are zero projects the solution shows, but as soon as I add one it disappears so I can't right-click and add another until I sort this setting out. It was the same in Visual Studio 2005, I was hopping they might have changed the default for VS2008, but no - the mob rule of the Morts wins.
Yes, I realise that I can go to the file menu to add a new project from there, but if I'm already focused in the solution explorer, I want to stay there. I don't want to make giant leaps across the screen to do these things. I want everything I need within easy reach.