Probably Sony. Nintendo is basically going to live forever, and Microsoft is hanging in there with all of the computer games they make.

i think Microsoft will die off first, Nintendo and Sony are too powerful [not according to some of these people though ].

I like Nintendo and Sony! Microsoft is goin down!

Nintendo will die first. Nintendo's been holding on to their gimmicks for to long. Most likely there console will die. They will hold on for another generation of handhelds. Then they will not make enough money to make the consoles.

Sony dies next It's been said many times Sony's running out of Ideas. It won't die as fast as Nintendo because they have the ability to execute properly and do not make gimmicks. Unfortunately Sony has lost the sight of what a gaming consoles suppose to do and will probably start making computers instead.

Microsoft dies last. After a long street and bill gates death. Microsoft will crumble. There console will stop being supported. They will leave that line of business. They will struggle to quickly make a new operating system. Only to be beaten by Sony and be crushed.

Nintendo will be bought out by a new company owned by a rich man seizing the opportunity of Nintendo's current weak state. Now this new company will own copy right to all of Nintendo's and Sega's characters and system and will focus on virtual reality. The true reason for Nintendo's sudden weakness will be a new gaming company rising in japan. Nintendo will fail to compete with this new company and Sony and Microsoft as well.

Sony will make computers and have some good fortunes.

Microsoft will be bought out by Sony, Sony will now control Microsoft, Mac and it's own computers and become richer then Microsoft was.

In the End what happens?
Sony will seize the opportunity and release a new Xbox console.
Unfortunately Sony will be beaten by the new company and it's virtual reality.
The New company will assume a position like Sony had.
The Other company in Japan will assume Nintendo's old role and span across the globe.

In the End there were three company's Sony and two others
You decide who won.
Was it all of them? (With the new assumed positions of them there all almost exact replicas of the former company's)
Sony (It technically lasted longer then the other two but dropped out of the race before them.)
Other(The other two company's ended up beating sony's console as what is happening with the XBox360)