ReSharper is probably the best plugin for Visual Studio. It extends your favorite IDE with a lot of incredibly useful features.
Note
ReSharper is developed by JetBrains (http://www.jetbrains.com). ReSharper v1.0 was released on July 21, 2004 as the second product of this company.
Thanks to the features, code generation and code templates, you will be able to write smarter code. Navigation and search will help you find things quicker. With code analysis and code cleanup, you can provide better quality software as ReSharper will find and highlight errors, potential problems, and bad practices in your code. ReSharper will support you with almost any kind of applications that you can write in Visual Studio.
ReSharper comes in the following three versions:
C# Edition
VB.NET Edition
Full Edition
These versions differ in support for the main language used in your projects. According to the name, if you are using C#, you should choose the C# Edition. If you are using VB.NET, you should choose the VB.NET Edition. Finally, if you are using both these languages, you should choose the Full Edition.
All other features, such as support for web development, unit tests, and XAML are the same in all of these versions except decompiler, which is not available in the VB.NET Edition.
Apart from the provided features, ReSharper can be categorized based on license. Depending on your needs, you can purchase any of the following licenses:
If you are a teacher, a trainer, a Microsoft's MVP (Most Valuable Professional), or if you are working on a non-commercial open source project, you can get ReSharper for free.
Note
For more information about ReSharper licenses, you can visit the Licensing & Upgrade page at http://www.jetbrains.com/resharper/buy/license-matrix.jsp.
ReSharper v8 provides support for Visual Studio 2013, 2012, 2010, 2008, and 2005. ReSharper works with all editions of Visual Studio except the Express Edition.
It is also possible to use ReSharper with Visual Studio 2003. ReSharper 2.0 is still available; it provides support for this version of Visual Studio.