HP Compaq dx7500 Core 2 Duo 2.8GHz Desktop PC w/ XP Pro

At Provantage.com, search for "KR785UT" to find the HP Compaq dx7500 Intel Core 2 Duo 2.8GHz Microtower Desktop PC (no monitor), model no. KR785UT#ABA, for $391.78. With around $17 for shipping, that's the lowest total price we could find by $12. It includes an Intel Core 2 Duo E7400 2.8GHz dual-core processor, 1GB RAM, 80GB Serial ATA hard drive,DVD-ROM, Gigabit Ethernet, one PCI express x 16 slot, a 3-year warranty, and Windows Vista Business with Windows XP Professional downgrade installed. (It's also eligible for a free upgrade to Windows 7, as mentioned here).