Quote:(there is no 2D component to DirectX - you just use one 3D rectangle basically)
You can use the Direct3DX library and its sprite class for 2D work in DirectX. If you don't mind a little obsolencence, you can also use DirectDraw.
I'm currently experimenting with code and I've just barely figured out how to do screen transitions without crashing my applications, so I plan on beginning scrolling & collision detection next.
The thing about deciding which game is right for you is to figure out your strong areas. An RPG doesn't need much physics or really responsive controls, but you have to be reasonably good at scripting. Pong requires physics, collision detection, and AI (unless it's 2 player only), but it's relatively easy to make your own sprites and resources for it.