ReSharper:: The Most Intelligent Plug-in To Visual Studio 2005, 2008, and 2010 - C# 4.0, VB10, LINQ, VB.NET, ASP.NET, ASP.NET MVC, XML, XAML, build scripts. Best-of-breed tools for code quality analysis, code cleanup, navigation, code generation, and unit testing, plus multiple refactorings and code templates.

Developer Productivity Tool for Microsoft Visual Studio

Download ReSharper 5.1!
30-day free trial (25.9 Mb)

Web Development: Code inspections, code completion, navigation, templates, and many more features for ASP.NET and ASP.NET MVC.
Code Analysis: View and remove all problems in your solution from
a single tool window; track value flow and method calls; upgrade loops to LINQ.
Project Maintenance: Project-level refactorings, localization pack, structural search and replace, navigation to library sources.
Visual Studio 2010: ReSharper sim-ships with the new Visual Studio. It now works with VS 2005, 2008, and 2010!

Continuous code quality analysis in C#, XAML, XML, ASP.NET, and ASP.NET MVC.
Instant fixes to eliminate errors and code smells.
40 solution-wide refactorings to safely change your code base, and 200+ code editing helpers.
Extended web development support with code inspections, code generation, navigation, and extended IntelliSense.
Navigation features to let you instantly traverse your whole solution.

Read more about these and other ReSharper features,
or watch ReSharper screencasts.