Comparing the Socket LGA 1366 Core i7 powerhouse against the upcoming Socket LGA 1136 Core i5 mainstream processors - namely the Core i5 "Lynnfield" 45nm quad-core and the soon to be dodo Core i5 "Havendale" 45nm dual-core with embedded graphics on the CPU itself.
According to sources the first Core i5 Lynnfield processors will start being sold sometime in mid September, just in time for Windows 7 [photo's courtesy of tweaktown].