After learning the procedures in multi-touch application development, and have experience with C++ you will need more efficient and more capable programming languge support as your ideas about multi-touch applications developing. Because you will need more complicated stuff both for graphical user interface and programming concepts. Therefore WPF and C# will help you for these needs. You can easily design simple GUIs by using xaml and then add codes. Time saving ! So, now I’m going to give sources for you to know which place to start.