Microsoft Store offers the Alienware X51 Intel Core i7 3.4GHz Desktop PC in Black (no monitor) for $849 with free shipping. That's $100 under our September mention and the lowest total price we've seen for this model. Sales tax is added where applicable. It features an Intel Core i7-2600 3.4GHz quad-core Sandy Bridge processor, 8GB RAM, 1TB 7200 rpm hard drive, Blu-ray disc combo drive, NVIDIA GeForce GTX 555 1GB video card, 802.11n wireless, and Windows 7 Home Premium 64-bit.

Of note, this system is eligible for a Windows 8 Professional upgrade for $14.99.