Talking about editors is like entering a minefield. As the Latin would say "De gustibus non est disputandum," which can be liberally translated as, "There's no arguing with taste." Editor and IDE preferences are highly personal, and I will therefore refrain from telling you which one you should use. I do, however, provide a list of a few popular choices, and I invite you to try them out at your leisure, until you find the one that's right for you.
Microsoft evangelists may occasionally use Notepad in their demos, but as a Microsoft developer you know all too well that without a serious IDE like Visual Studio, writing ASP.NET or .NET desktop applications would be a nightmare. Your proficiency in Visual Studio may make or break your productivity.
In the Rails world there isn't an official IDE and we're not big fans of drag-and-drop tools either. The truth of the matter is that Rails doesn't need either of these two things. Most Rails developers are very happy about using text editors. As a matter of fact, when programming in Ruby or in Rails, a good text editor is all you really need. Even something as simple as SciTE, which we installed through the One-Click Ruby Installer, is probably sufficient.
C# and Visual Basic are both relatively verbose languages that take advantage of a huge framework. Ruby is so expressive and concise that an IntelliSense system like the one you are used to in Visual Studio would be helpful, ...