Well, 8 core CPU should be more common in 2012, so maybe Mircosoft goes that way. But it could also be 4-6 cores only. And I don't know about the RAM, I don't think consoles needs as much RAM as computers, but 1 GB RAM would be a must. And if they really boast the cache memory in the CPU to about 4 MB or more, then even better!
And I agree a bit with FilaBrasileiro about the GPU. The most important thing would be to cover the things about the GPU that could be better and add some performance. If I was the one putting the next Xbox together I would also add another GPU that was simpler and allot cheaper then the regular one to either boast the graphics capabilities in some kind of (hybrid) Crossfire/SLI thing or/and as a extra processor for physics and other data to be calculated.
Thanks to Wii, next generation might not be so much about pure performance, rather more about getting as much upgrade to the hardware at as low price as possible with maybe two types of control setup to battle Nintendo and Sony at all areas.