I recently noticed that my VS 2008 SP1 crashes whenever I try to add items using Toolbox > Choose Items. This was a pain since I wanted to use the Ajax Control Toolkit in my project. Googling provided three solutions. The first two are listed here. But the one that worked for me was to start the studio in safemode using ‘devenv /safemode’ and then to run through each of the tabs accepting any acceptions raised, and then to restart the studio in normal mode.
Visual Studio 2008 SP1 crashes when adding items to the toolbox