Intel Q6600: http://www.newegg.com/Product/Product.aspx?Item=N82E16819115017
Nice choice. If your looking for a good Dual Core try also the E6850 (3.0 GHZ, 1333 FSB). In a cpu shootout Tom's Hardware held the E6850 beat the Q6600 in certain test. May be something to consider since the cost are the same (not on NewEgg though).
There is alot of room to save cost. If your willing to go up to $1800 there is alot you can add on like additional HDD's, add a CPU cooler like a Zalman 9700NT (http://www.newegg.com/Product/Product.aspx?Item=N82E16835118020&Tpk=9700nt). You can go with the GTX card if you want or find a decent monitor and go dual screens. You can also go higher up on memory to faster DDR2 1066 modules. Alot of options as well within what i built here. I tried to keep the cost descent but without any sacrifices. This is a good starter point as i am sure other posters will build on this as well.