.Net Winforms

.Net Winforms are the part of the Microsoft's .Net Framework that is used to develop Windows applications.

I use Winforms as my primary development language for almost all the same reasons I use ASP.NET

Winforms is Object Orientated. For the non-techies, this describes the style of the programming code. Object Orientated code is well organised. Applications are split into logical chunks called objects and each object encapsulates all logic related to it. This makes it easy to navigate the code, but also eliminates any tendency to duplicate the same code time and again.
Winforms is supremely logical. As described ASP.NET encourages well formed code.
Winforms is reliable. Mostly due to all of the above.

It's also constantly moving forward. New versions, beta releases, new techniques, etc are constantly coming forward. This keeps me busy, but also (as I'm a geek) excited about the latest thing.