This deal has ended.
HP has their Pavilion s3700z Slimline Desktop on sale for $299.99. Click "Customize and Buy," and add the 20" monitor. At checkout, enter $30 off coupon code SV2132 to drop the final price to $449.98. It also features a 2.3GHz AMD dual-core processor, 2gb memory, 250gb hard drive (500gb is only $50 more), 16x DVD / CD burner, 15-in-1 memory card reader and Windows Vista Home Premium. Shipping adds $29. Sales tax charged in most states.