I was working on few demos based on VSTO so that I can present them during GulfGeeks conference later this week.
I am using VSTO/VSTO SE on top of VS 2005. All the add-in projects are working absolutely fine. The problem comes when i want to use VS 2005 project templates for document level office projects. I am unable to have a design time experience even on the projects that I created before installing VSTO SE. But the interesting thing is that I am able to run old vsto based solutions, that means that run time is behaving fine. I have posted query on a private MVP new group.
I believe all such issues will be taken care of by the time Orcas is released!