Productivity Power Tools
Probably the best code focused extension for Visual Studio 2010 is the amazing Productivity Power Tools. It includes such gems as the Solution Navigator which lets you navigate to classes and members, search for references, and filter your solution to show only checked out files.
NuGet Package Manager
NuGet is an awesome open source package manager for the .NET platform, which includes a very large amount of third party libraries ready to use in a couple of clicks. Or, if you fancy, by using a PowerShell console. They totally get extra points for the PowerShell integration…
F# Outlining
The name pretty much describes what it does. Visual Studio 2010 was a pretty massive release for Microsoft, including F# for the first time. This is why I totally forgive them for not implementing outlining support for this fledgling language. Fortunately someone else did their job for them.
Spell Checker
Everyone wants to have properly spelt comments, especially when you’re using the XML comment features in the .NET languages to produce documentation for your customers. While this plugin is pretty simple, it works a treat and even supports custom dictionaries.
Python Tools for Visual Studio
Not just an extension, but a whole bunch of Python related win for Visual Studio. This latest version works with both CPython and IronPython which really increases the scope for these tools.
Don’t forget to couple these guys with the Microsoft Web Platform Installer for great justice.