I came accross 'PowerCommands for Visual Studio 2008'. It looks to me like one those free tools that you 'just should' have. Not a killer app, but no cost, no learning curve, and it makes life easier. The 'Collapse All' command, which collapses all projects in the solution explorer alone makes it worthwhile. I'm liking it already.
Edit Project File looks real useful if you have embedded MSBuild community tasks.
Hmmm ...'Undo Closed' looks interesting.