End of year... that's the end of C2D... but we all SHOULD miss it dearly.
In all honesty, we should pray that Apple keeps the C2D and improves the MBA in other aspects... for example, better 320m GPU, 8 GB RAM option (4 GB Standard), faster SATA-III drive controller, faster SSD, USB 3.0, LightPeak (if ready), better software, better OpenCL integration between all applications, better OS X, better graphics drivers, much better OpenGL, and other minor improvements like glass trackpad. The least concern should be the CPU.
However, Intel pushes its damn marketing so well making the end users believe the only way to speed up their computer is to buy a faster CPU. With Intel ending production of C2D at the end of 2010, Apple will be forced to move beyond C2D.
I believe we will probably see Core i7-6x0LM low voltage Arrandale CPUs. It is the direct replacement for the SL9x00 series C2D CPUs found in the current MBA. In addition, Apple will most definitely disable the IGP and opt for an AMD discrete GPU. The alternative would be to move to AMD CPU/GPU/Chipset. I guess there may or may not be a combo that would work in the MBA. I personally don't care about the CPU at all.
I care about the GPU and all of the other things I mentioned as best ways to improve the MBA. However, I expect an MBA to move to Arrandale between October and January. I expect the MB, 13" MBP, and Mac mini to all get updates by the end of the first quarter 2011. I suspect a 5430 GPU in the MBA, 5450 in the MB, and 5470 in the 13" MBP and Mm. The 5430 at 7W TDP is doable for the MBA. The series allows Apple to create and maintain one driver set, OpenCL, and etc for all these Macs. When the 21.5" iMac is updated again, I suspect it will follow the same GPU and chip series as the others (MBA, MB, 13" MBP, Mm).
I am in no hurry for Apple to leave C2D behind. In all honesty, I would be happy with the exact same C2D 2.13 GHz CPU, with an Nvidia 320m, 8 GB RAM, SATA-III drive controller & 256 GB Toshiba SSD, IPS display, and glass trackpad. Hell, I would be happy to pay $4k for such an MBA.
Intel crapped on Nvidia and ALL of its customers when it forced Nvidia out of the chipset/GPU market. Us customers are the BIG losers. Intel did this to give itself some time to "catch up" with Nvidia's technology. Now, while Nvidia cannot afford the R&D to further the GPU/chipset system, Intel surpasses them in a few years... then Intel acts like it never meant to push Nvidia out and it lets them back in before there is a final determination in the case. We should NOT want Intel in our Macs. As long as the GPU is more important, we should focus on AMD and look for Apple to develop its own SoC in five to ten years. Hell, our iPhones will catch up with the MBAs with the clock speed at which the SoC is increasing.
This is a no win situation... unless Apple can fit the discrete ATI (now AMD) GPU in these Macs. We will get a better system ONLY if there is an Arrandale/Sandy Bridge CPU with an IGP disabled, and a discrete AMD GPU paired with it to give us better CPU performance and better GPU performance.