I have been thinking about my final year project topic and to be honest I want to create something GREAAAT like many others. I know C,C++,Java and Python (Python is getting quite popular these days).. I want to create a small-scale application like Blender (graphics rendering software) any tips for me? I prefer using OpenGL and it's shading language rather than Direct3D since it is open-source. 
Tell me the stuffs I should know to pull this off and also if the combination of python and OpenGL a good choice for this application ?
A small object-viewer should definitely be possible. That's something you can build and add features upon, depending on how much time is left. I would do the visualization and movement in your scene first, then some basic interactions with your objects (translating, rotating, etc.). The final step would be adding tools (edit polygons, sculpt, etc.). If you are fit enough in C++, OpenGL and Software-Architecture on a larger scale it should be doable.
Creating small scale application like Blender?