Um...forget the e6700, just get an e6420 or e6320. They can easily overclock past the e6700, and then some....but as peterhuang said, Intel is slashing prices, as well as introducing new C2Ds, on July 22. In that case, you should go for the e6750, which will be around the $180-190 mark. It is said to overclock quite easily to at least 3.5+GHz.
For the motherboard, theres one hot motherboard right now, and thats the
Gigabyte P35-DS3R....futureproof, and an overclocker's dream.
Power supply....I would suggest the
Corsair 620HX.
Hard drive....
Samsung Spinpoint 500GB HDD, for only $110. Great deal. One of the faster 7200rpm hard drives out there.
I would also strongly suggest, you get a full tower case, such as the
Thermaltake Armor, since you're getting the GTX.