Thanks to everyone, You guys know your ####!
So just to clarify the stuff that has been posted.
SDL can be used in conjunction with OpenGL, but there is only the cut down miniGL version available for the Amiga? The GCC compiler is a tried and proven compiler for the Amiga? The SDL is good because it provides an API that interacts with all aspects of hardware: I/O, sound, and graphics, where as OpenGL provides the API for graphics programming?
Thanks again fellas, by the way is any of you guys currently developing a game/games for the Amiga at the mo?