Below is a list of tools, plug-ins, packages, etc that you should really consider using if you are doing development for ASP.NET MVC.
Sidewaffle - custom templates. Can consume them from library or create own
Glimpse - amazing view into all things. particularly performance. Scott Hanselman has a good review of it.
ZenCoding - very cool html coding that greatly reduces typing of html tags
Web Essentials - extends Visual Studio, including design time edit from browser
Less - gives variables, etc to CSS like files that we can generate css files from automatically
WURFL - on nuget for reliable device detection (mobile, table, google glasses, etc)
Automapper - Copying data automatically from object to another similar object