The open computer

[opendriver]

http://www.psystar.com/

Any OS, Mac, windows, Linux (Ubuntu)

Base model starts at $399, and for that you get:

• no operating system included
• no keyboard, mouse, or monitor included
• 2.2GHz Intel Core 2 Duo E4500 Processor
• 2GB of DDR2 667 memory
• Integrated Intel GMA 950 Graphics
• 20x DVD+/-R SATA drive
• Gigabit Ethernet
• 4 rear USB Ports

Check out the site a little more and you can find the "pro" model for $999, which offers:

• no operating system included
• no keyboard, mouse, or monitor included
• 2.6GHz Intel Core 2 Duo E6750 Processor
• 2GB of DDR2 667 memory
• nVidia GeForce 8600GT with 512MB of RAM
• 20x DVD+/-R SATA drive
• Gigabit Ethernet
• 6 rear USB Ports

And you can customize them as you wish, check out Engadets review with benchmarks and video:

http://www.engadget.com/2008/04/30/psystar-open-computer-notes-benchmarks-and-video/

Lawsuit in T-minus 5,4,3,2...