Nehalem is a rather interesting architecture and Lynnefield is the next Nehalem quad-core to come in Q3 2009. The first one that launches in mid-November is Bloomfield, the one that we call Core i7 now. There is always a server chip called Nehalem EX.
Lynnefield is a quad-core with hyperthreading that will use Ibex Peak, now P55 chipset, and we've learned that this chipset also supports DDR3. Actually, it’s the CPU that has the memory controller now, so it’s up to Intel to make a Nehalem generation CPU with DDR2 controller, but as far as we know this won't happen.
Year 2009 is DDR3 all the way for Intel and even the notebooks are moving toward this theoretically faster memory. It looks that Havendale dual-core Nehalem with IGP will also be exclusive to DDR3 and this makes perfect sense, as DDR3 prices dropped down and the price difference between DDR2 and DDR3 is negligible.
There is also some indication that the P55 board that you purchase in Q3 2009 might actually not work with Havendale due some architecture differences, so there might be a new revision of P55 for this dual-core chip. We will keep asking around about this one; but bear in mind that Intel changes its minds on a monthly basis and we are talking about the stuff that will happen in nine to twelve months from now.