Uhm, today also 1024 textures are no problem. The new GeForce 8800 GTX will have 768MB graphics memory, and if your game is released in about 1 or 2 years, everybody will have cards of this kind. 512 is nice and sometimes enough, but too small for a today's game - especially if you don't use any kind of shaders to make it look nicer [normalmapping e.g.]
