What will the game play be like? The perspective of the graphics will be influenced by that. The amount of graphics can be minimized initially with room for expansion, so for example if you make a game like those zelda type games pictured above, you can make 4 angles (or even 1 mirrored east/west view used for all directions), and increase it to 8 later if people feel like it. Or if it's first person you could have them always facing you and then add more angles later if people are up to it. Use an iterative process to first create basic graphics, then add animations, more angles, and other stuff later if people are up to it.