Buy.com offers the factory-refurbished Compaq Presario SR5152NX Athlon 64 X2 2.1GHz Desktop PC (no monitor), model no. HPGC666#AAR, for $299. With free shipping, that's $460 under the lowest total price we could find for a new, factory-sealed unit. It includes an AMD Athlon 64 X2 2.1GHz dual-core processor, 3GB RAM, 250GB SATA hard drive, media card reader, dual layer DVD burner with LightScribe, 6-channel audio, keyboard, mouse, and Windows Vista Home Premium.

A 90-day warranty applies, although it's unclear who supports it.