So the E6400 does between 3.2 and 3.6Ghz depending on your luck and other hardware (cooler, ram, motherboard).

I often saw people say the E6600 is not worth the money over the E6400 because the E6400 can overclock to E6600 speeds easily. But... E6600 can overclock as well. What speeds can be expect from E6600, and do you think they would be worth it? (Especially with the new 8800 cards, where CPU speed matters more then before)