Newegg has the Acer AM3985-UR20P DT.SJQAA.001 3rd Generation Core i5 Quad 2TB Desktop for $620 - $70 off with coupon code
EMCYTZT2538 [Exp 11/18] =
$550 with free shipping. Only thing lacking is a good graphics card to make this a nice mid-range setup.
Intel Core i5-3450 Quad-Core 3.1 GHz, 10GB RAM, 2TB HDD
Intel HD Graphics 2500, DVD±R/RW, 802.11n, Win 7 HP x64