Adds interim language support until Visual Studio catches up. Settings can be shared across teams of developers. Alternatives: Productivity Power Tools VC Commands 2010 Devexpress Code Rush Telerik Just Code VS 2010 Extension Manager
Mindscape Web Workbench
Add Sass, Less & CoffeeScript support to VS2010 "See old friend, I brought better code than you did"
Web Standards Update for VS2010
Adds support for HTML5 & CSS 3 to VS 2010 SP1 HTML 5 Browser API (GeoLocation, Local Storage) CSS3
Manage common packages and dependencies for your projects Right click on references and manage nuget packages. Can update installed packages. "We've built a deal a day website because they are very rare and hard to come by."
Continuous Integration Server
Chrome Developer Tools