GameEx is considered to be the most powerful, stable and feature rich gaming front-end (emulator launcher) for MAME, GameBase, Daphne, PC Games and all command line based game emulators, along with being a complete Home Theatre PC solution or plug in for windows media center. It is a freeware game emulation application that's modern, well-designed and advanced.
Here are some screenshots to illustrate the features and user interface of this application: