VSTO - Visual Studio Tools for Office

I went to the VSTO: Roadmap to the Future talk by Mike Hernandez last night organised by the MTUG in Dublin. VSTO will be in the box with Orcas (as opposed to being a separate download as has previously been the case), so in Orcas if e.g. you go to File->New Project you'll see the option to create app level add-ins for Excel, Outlook etc. in the same way that you see ASP.NET Web Site as a project type.  There'll be visual designers for customising the Office 2007 Ribbon, custom task panes, Outlook Form regions etc. ...and it turns out you can use WPF controls in the VSTO designers as well - should make for some interesting add-ins.

Also the deployment and security model have been improved - ClickOnce deployment now for your OBAs. In the meantime until Orcas arrives you can use VSTO 2005 SE to target the 2007 Office System.