Newegg offers the refurbished HP DC7800 Intel Core 2 Duo 2.66GHz Desktop PC for $55.99 with free shipping. That's the lowest total price we've seen for any HP DC7800 desktop. (It's a current price low by $54.) It features an Intel Core 2 Duo 2.66GHz dual-core processor, 2GB RAM, 160GB hard drive, DVD-ROM, Gigabit Ethernet, and Windows 7 Home Premium.

Note: A 90-day warranty applies, but it is unclear who backs it.