Originally Posted by Tronic
If I were you, I would stay far, far away from DirectX. This isn't one of those "DirectX sucks" opinions at all, it's just really not the easiest API to learn.
OpenGL will create your game with ease, and it will be a hell of alot easier to program in than DirectX. OpenGL's function and variable naming schemes are compact, consistent, and understandable. Compared to DirectX, OpenGL is alot easier to learn and understand from the start.
The learning curve for DirectX is just a bit steeper than with OpenGL. DirectX is a very powerful API, but the features you'll be using in your game will be much easier to program with the OpenGL API.