Unity 3d is a revolutionary 3d game development tool.
Cheetah 3d is a wonderful 3d modeling, animation, and rendering tool that, for me, made working with 3d graphics fun again.
Blitz3D and BlitzMax are amazing tools for prototyping and developing games, and have a great developer community
Real Software the developers of RealBasic, a superb tool for Macintosh, Windows, and Linux development
ForeSight is a game I originally designed in 1985, and which is currently going into a new edition
Penny Arcade is a website you'll either love or ... meh