Got a ASUS P5N32-E, now what CPU makes it scream?

I building a Core2 machine with a ASUS P5N32-E. With the expected price drop, which chip should i put in the machine for around or under 400usd? I would prefer a Core2 Quad.

I want to OC the thing, so i'll take RAM tips too .

The cheapest quad is still over 800 USD. With the price drops, the e6700 dual core should be under 400, as well as the e6600 (which might be as low as $230 or less). Both of those will run like crazy. With either of those, the multiplier is high enough that you can use virtually any decent DDR2-800 ram and your processor will hit a wall before your ram will. I personally use G.Skill, and it runs solid for me. They are the GBHZ model 2x1 gig matched pair with the black heat spreaders. Found a link for you.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231065