An open source NES Emulator for Windows and Unix that features solid emulation accuracy and state of the art tools for power users. For some reason casual gamers use it too.
win32 autobuilds @ https://ci.appveyor.com/project/zeromus/fceux/build/artifacts
But you might like mesen more: https://github.com/SourMesen/Mesen
You should get releases from here: https://sourceforge.net/projects/fceultra/files/
That's because github forces us to use tags we don't have for releases.
2.2.3 is the most recent release but most people are using the autobuilds.