Atari 2600 is the most well-known model, it is the most common one, and it has the most games made for it. It is also the cheapest one, and the most primitive one when it comes to graphics and sound. The Atari 7800 is equivalent to an NES graphically (well, maybe just below NES), and it also plays the Atari 2600 in addition to the 7800 games.
Even with its small library of game N64 is the best console of all time. It was powerful, innovative, and boasts a very high quality to quantity ratio. Some of the best games of all time are on N64 such as both Zelda Ocarina of Time and Majora's Mask, Super Mario 64, Banjo-Kazooie, Star Fox 64, and Conker's Bad Fur Day.
One a side note. I think that the PS4 is probably the best console Sony has ever made, but the exclusive game support is pretty sad. Thank goodness there are some fun multi-plats to play on the PS4. If Sony would ever start releasing some true interesting exclusives, the PS4 could be their greatest console.
Especially since "ever made" implies every console made ever, in which case I can say "TEH SUPER MARIO BROS IS GOOD!" Playstation, Playstation 2. The Xbox 360 may be the most viable platform this generation for general purpose gaming, but the truth of the matter is the dominion that the Playstation 1 and 2 held over the market in their respective eras basically stamps out the Xbox 360 in the grand scheme of things.
If you look at old forum posts from ~2000 many people honestly believe that the PS2 is going to be doing >50 million polygons in game in comparison to Dreamcast doing 3 million, and there's a very widespread feeling that when the big consoles arrive the Dreamcast is going to be very, very underpowered.