Visual Studio 11 Developer Preview is now available (actually, it was released a little while ago) and I only just got around to giving it a go. Although it doesn't seem a whole lot different to VS2010, there are a number of improvements and additions:

• async and await keywords
  These keywords allow for some impressive asynchronous functionality to be handled (I briefly covered this in a previous blog post)
• Built-in bundling and minification of client scripts
  This allows you to bundle up JavaScript and CSS into single files, to remove unnecessarily large numbers of requests and save on file size.
• Integrated Anti-XSS encoding routines
  These anti cross site scripting features were available previously as an external DLL, but are now part of the core functionality.
• Support for HTML5 form types
  Types such as email, tel, url and search are now handled appropriately.

There's more, but you can check out the full details here.