I agree with this as well. I would hold off on Applecare at purchase if you find you don't have the money immediately, but I would suggest that before the one year warranty is up to get it. Should the RAM fail the it looks like something of great expense would need to be swapped out: motherboard or entire computer.
I would also suggest a good external back-up strategy for this should that actually happen. Not trying to be a fear monger, but even high quality RAM fails occasionally.