While we thought that the Bloomfield, a high end version of the Nehalem with DDR3 support on three channels and which fits into the Socket LGA 1366, would be reserved to "Extreme" and "Performance" segments for some time, the latest Intel roadmap says otherwise:

Not only will it be found on part of the "Mainstream" segment but also it will arrive in the fourth quarter of this year.

Besides the frequency, the speed of the QuickPath Interconnect bus and DDR3 support will enable Intel to better differentiate its Extreme version. However, given the
first very encouraging benchmarks of the model set at 2.66 GHz, this should be amply sufficient for some time.
Also, note the appearance of a 45nm Core 2 Q8200 which will progressively replace the Q6600. As for the Core 2 Duos, they are on the entire "Mainstream" at least until the second quarter of 2009. We just have to wait and see when the
Lynnfields and Havendale arrive, the mid/low level Nehalems, which were previously expected out in the first half of 2009.