Dear Carsten and others,
I have a similar problem. I installed the 1.6 on Win7 with VS2010 ultimate 64bit. When I check the event log it claims a succesful install.
I installed and repaired several times, rebooted checked under all new project templates, tried to add a new item to an excisting project.
But nowhere can I find the WSP templates. Is there anywhere I can 'unhide' the templates or where I can go around the UI to use a certain template which would be available in the file system.
BTW I also checked the externsion manager in hope off - would be nice to find the WSPbuilder as an online extension.
I will also try to install at home -and will watch this space, but looking at the history I'm worried there is no solution.