If you are looking for a low-cost All-In-One that somehow reminds me of a Darth Vader version of Humpty Dumpty, the Atom 1.6GHz-powered eMachines EZ1601-01—loaded with Windows XP and 1GB of RAM—may be the ticket for just $400.

eMachines EZ1601-01 All-in-One Desktop
• $399.99 (MSRP)
• Microsoft® Windows® XP Home
• Intel® Atom(TM) Processor N270 (1.6GHz, 512KB L2 cache)
• Intel® 945GSE Express Chipset
• 1GB DDR2, 533MHz memory
• Integrated Intel® Graphics Media Accelerator 950
• 160GB SATA hard drive (1)
• 8x DVD+/-R/RW SuperMulti double layer drive
• Multi-in-one digital media card reader
• Integrated 802.11b/g Wireless
• 5 USB 2.0 ports (2 side, 3 rear)
• Integrated 18.5-inch widescreen LCD with 16:9 aspect radio
• Built in speakers
• Embedded high-definition audio support
• Keyboard and optical mouse