Not long ago I had no idea what the point of ASP.NET Dynamic Data was.  I simply could not 'grok' it, until very recently when I tried using it for a client's CMS.

Nice to see that finally ASP.NET MVC has been released!  Been using it since the very first preview, and it's been a blast.

One thing that has certainly sped up my development time is using ADO.NET Data Services with my AJAX.  Instead of having to build controller actions or a web service to grab the data, i can just consume it from the data service directly.