This question is assuming there is no Nintendo?
But what a sad world without Nintendo.
A different hypothetical would be:
If Nintendo dropped its hardware line, and sold equal portions of all of its IP's to both Sony and Microsoft, which console would you buy?
But even that is hard to answer, since for me it would come down to whichever has Mario.
This is why questions like this are hard for me to answer.
there would never be a world without the wii.
if it wasn't the wii, it would have been something else that took the consumer friendly low price point route.
For the PS3 and 360 to be the consoles they are, a wii is needed for contrast.