NES and Famicom Audio/Video mods
mmmonkey will be adding to this page gradually (as soon as it gets its hands on some NES consoles!)
From what mmmonkey has read, you can emulate Stereo Sound, although the NES and it's Games are only Mono, it's meant to improve the sound a lot. Details can be found here.
mmmonkey thinks that some Famicom/NES consoles only output an RF signal, it is possible to add a Composite Video out onto the console apparently, but mmmonkey hasn't seen a guide yet (although mmmonkey is looking and has heard it's obvious once you open the system up).
mmmonkey has also read the some French Secam units support RGB out, sounds good - although some people report that the colours don't look correct.