How do you create an application with a unique GUI like Valve's Steam?

Question

Valve's game manager application, Steam, has a very unique user interface, with custom buttons and windows. How would you create a Win32 application that has such a look?

Answer 1

Pretty much every windows common control supports custom and/or owner draw (not the exact same thing), that just leaves the dialog itself where you can customize its look by handling WM_ERASEBKGND and WM_PAINT or WM_NCCALCSIZE,WM_NCPAINT (If you don't want native titlebars and border etc)

As you can see, to do a custom GUI requires you to paint every control yourself... (And keep in mind that a lot of people hate skinned apps and would rather just have a native looking app)