As someone who spends a great deal of time analyzing the financials of AMD, Nvidia, Intel, and others...
AMD absolutely needed to do this deal; without it, bankruptcy would be a very legitimate concern in the face of the widening gap between Intel and AMD in PC processors/APUs, and AMD's practical nonexistence (and lack of focus) in the higher margin, higher ASP segments of the GPU (Quadro, Tesla) business that Nvidia dominates.
Nvidia is a well oiled machine that executes and delivers time and again, learning quickly from its past mistakes, picking the battles it fights judiciously, and ultimately wins. AMD is a company that in 40 years has done nothing but lose money, as it has been hampered by piss-poor executive decision after piss-poor executive decision.
I don't know what the motivations for the "AMD fans" or the "Nvidia fans" are here, but let's not forget that these are businesses and we should ultimately judge them by their success at operating like them. Nvidia is a winner, and AMD so far has been a loser. That being said, winning the consoles may be what it takes to get them to cash flow positive in 2H 2013, and I suspect that they gave Sony and Microsoft very, very nice deals here.
Oh, and to the people thinking that PC games will suddenly be optimized for GCN and leave Nvidia out in the dust - not going to be so easy. Nvidia spends quite a bit of money working with developers to make sure things are pristine, and as you can see with Nvidia's execution on the driver side (remember the TressFX debacle that was quickly resolved?), the company will make sure to keep its dominant position in PC gaming barring another Fermi-like disaster.
Kepler was a brilliant design that was much cheaper to make than AMD's parts, while at the same time performed well enough where it counted (PC graphics) to warrant premium ASP. The really high end compute stuff sells for $1,000 and is routinely selling out. Nvidia knows how to run its business - it's AMD that has problems. I know gamers here love that AMD cards are cheaper, but believe me this is not by choice.
Anyway, get back to arguing about whether Nvidia should have taken the low margin console business - but my simple response to this is that Nvidia has a much smaller headcount than AMD, so it needs to partition its resources effectively into places that have very high ROI. Look at GRID, look at Tesla/Quadro, and even look at GeForce. High margin money makers with great technology leverage across the product lineups. Tegra, which currently is NOT profitable for Nvidia, has a real shot at becoming a very nice moneymaker for the company. Nvidia has the modem, has the GPU IP, has the software guys, and is producing better and better SoCs and winning bigger and bigger designs each year. Gross margins for mobile SoCs are 50%, so all that Nvidia needs is volume, which should come as it rides the secular tablet growth wave and as consolidation hits.
Nvidia did not need console wins, but AMD is likely to benefit significantly from it.