The Famicom (Family-Computer) is just the Japanese version of the NES. Identical hardware and software to the NES, but in different plastic casing.
The American and European versions were the NES ("Nintendo Entertainment System" and looked exactly the same as each other but entirely different casing to the FAMICOM.
At the very end of its life there was a top loading one that looked a bit like a snes, that was only released in America.
The ONLY other offical NES sytem that I know of is the Arcade machine "Play Choice 10"
There are LOADS of clone NES systems that look different, most of them being Famicoms (ie only play JAP games) or come with loads of game ROMS built in (ie the 128-in-one style "arcade" joypads that plug into your tv you get at markets. These are illegal. And Toys-R-Us sell them. and they are ILLEGAL. and SOLD IN TOYS R US. (Sorry but that annoys me.)
An unboxed NES system costs around 25 pounds on ebay, a boxed one can reach 50-60 for the normal packs, or 100 for the one that came with a robot. The local second hand shops near me sell them for around those prices too. The games are worth 3-10 pounds mostly although there are some VERY rare ones which collectors go nuts for.
Megaton - Wow nice, 3 of the best games