In VS2008 you used to be able to collapse all projects via a right click menu option in the solution explorer, this feature has disappeared. I found this to be fairly useful when opening large projects for which I did not already have user settings (i.e. from source control) as all projects are expanded by default in this case. Collapsing them allowed me to find the relevant project a lot quicker. Note that we have over 90+ projects in some solutions which makes collapsing them one by one time consuming.