To strictly answer the question which is best, I voted XBone. It just is a superior system to everything that came before it,.as is almost always the case with a given piece of current gen tech.

If we want to talk about which one was the biggest deal in its time, that would have to be Atari 2600, followed by Genesis and XB360. 2600 was *the* machine at that time. The competitors that did anything were just 2600s by other names. Genesis, while it had a significant competitor in the SNES, was really the only one trying new things (Sega CD, 32X, awesome games. The 360 is the systems that solidified MS's place in the industry, and had a massive game library.

Megadrive?

360 easily, too many gems. All though it’s traditional output slowed after Kinect was a thing, it’s 2005-2010 lineup alone is worthy of being the best console outside Sony/Nintendo

Though if you want to get technical the Xbox One has 360s best games BC on top of Xbox One games so Xbox One X would be the actual winner. 

Sega Genesis by miles and miles.

Probably the Xbox 360.

ColecoVision.

Dreamcast was TRULY a console ahead of it's time. For those who were old enough to game on it always describes it that way initially. It had a stellar library for it's short lived existence. I still have mine in pristine condition.

The 360 is certainly 2nd in my eyes. I absolutely loved it. The exclusives it has is by far some of the best.

SNES didn't have awesome games? Super FX chip wasn't trying new things?

It was called the Genesis in America but here in PAL regions it was called Megadrive.

I hear this a lot and I must say I disagree.

I thought 360 had a tons of great "traditional" games from 2011 onwards; Gears of War 3, Witcher 2, Halo 4, Bioshock Infinite, Wolfenstein The New Order, Dishonoured, Batman Arkham City, Metro Last Light...

As a 360 owner I never felt short on stuff to play in 2011-2013.

As someone who was team Sega in the SNES era, I have to go with the Genesis.

I know, I was just asking myself if I think Megadrive to  the best  console outside Sony/Nintendo XD