Fusion: A Sega Genesis emulator that works great on older computers with Windows 9x. I know some of these have been mentioned here before, But I'll go ahead and list the emulators I mainly use here. I remember having to press a certain key just to go back to the ROM loading window. People said that ZSNES was better but, I had a hard time trying to even load a ROM with it. It is one emulator I would highly recommend. I think I can recall a Chinese version of this too.
FCEUltra - The NES emulator I used most often, and one of the best I had used.
When I used to do emulation gaming years ago, I used the following: