Intel's 45nm dual-core E8600 is rumored to arrive on August 10th and retail at $266. This is the very same chip that currently holds the SuperPI 1MB record.
After this date we are not aware that intel plans to launch any faster dual-core, Core 2 duo generation of CPUs.
This CPU is a slight speed increment of currently available E8500, and as you can imagine the 3.33GHz version will be called Core 2 Duo E8600. The E8600 will cost $266 at launch and it is scheduled for August 10 launch.
At this stage it looks that this will be the fastest Core 2 Duo CPU of all time, at least when it comes to dual-cores; and Nehalem generation will take over the dual-cores but only in Q3 2009, not before. Until that time, it looks that Core 2 Duo E8600 will be the fastest dual-core on the block. 
