Wait, they're different? If so then someone tell me which one is the best. That means I want to download the first one (map 2 dif) and the one that's best, not all four.
Milkshape costs money but its interface is easy to use.
Blender is more complex, but it's free.
I'm not sure about the 3D studio one but it might be worth it to look into it.
Also, I hope you realize all of the above programs (excluding map 2 dif) are for modeling, and if you were planning on scripting then you are headed down the wrong path.