My bets go towards the merom using 667mhz DDR2, PC5300 SO-DIMM RAM just like the current Macbook and Macbook Pro. I say this because the only move they could make would be 1066mhz RAM on the SO-DIMM platform. This is highly unlikely, for two reasons: 1. PC5300 is only going down in price; 2. 1066mhz SO-DIMM RAM doesn't even exist yet.
What coastertux said does make sense. It should go down in price between now and then. But I hope you have read up the differences between the merom and the yonah. There are benchmarks that prove there won't be much difference (at least on the PC side). The only thing you will be gaining by going with the merom is 64bit, and the fact that you will probably be in the window to get leopard for cheap or nothing (can't remember what the standard procedure for Apple, new os launches, and recently purchased hardware). But also realize that even though the OS will be 64bit, it'll still run 32bit software about as fast as the yonah. The only possible major gain in performance will be applications that are coded to take advantage of 64bit. And you'll probably be waiting as long for those as we all waited for UB binaries. Granted alot were availble early on, but we are all still waiting for a UB version of Photoshop. I'm willing to bet you'll have to wait till CS4 for 64bit support as well.
So take all those things into consideration whilst you wait for a merom Macbook/Macbook Pro.
