Unreal Engine 3 is a complete game development framework for next-generation consoles and DirectX9-equipped PCs, providing the vast array of core technologies, content creation tools, and support infrastructure required by top game developers.
Loved the engine ever since I started using it. Very easy to use and very visual, which I like, from the editor window to creating materials and particles. It's a powerful tool, especially for creating 3D games with a high level of visual quality quickly. And for the level of quality you get out-of-the-box with this engine, 25% royalty after $50,000 is MORE than fair, and I have to thank EPIC for that. Can't wait to see the public release of UDK with UE4!