What are the best free 3D game creator softwares?

I am looking to create a 3D game like Halo but I need the apropriate software. I also want it to eventually have MMORPG capabilities... but not yet. I am not looking for some childish 2D game maker, like Microsoft Popfly, but I do want it to have as little code-learning as possible. Any suggestions on freeware products that can make games like Halo? I need the physics, collision detection, lighting effects -- everything.