This is kind of a basic and stupid question…
Sometimes when I’m mucking about, I have a tough time telling which reference I need to add to a project to get access to a specific thing. How do you all quickly tell which library contains the code your interested in?
The documentation for the Microsoft and GHI libraries have the associated DDL Name (reference) and namespace (using …) for all of their classes.
Long ago an employee convinced me to invest in ReSharper (ReSharper: The Visual Studio Extension for .NET Developers by JetBrains) which is now the first IDE extension installed for me.
It works out the references for you 95% of the time, and is an awesome refactoring and helper tool for C#.
The main problem being that the VS Express edition does not support addons and plugins… so no chance on my own to use resharper… Licenses of VS are really expensive!!!
Some really good deals can be found on eBay 
Just don’t tell MS where you got it… I don’t believe eBay is an authorized reseller 