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Dell SB has Vostro 200 Mini Tower desktop for $419 with free shipping if you choose Next Business Day shipping.

Please note, the system has almost no options you can change.

Specs:

Vostro 200 Mini Tower Case (not slim tower)
Intel Core 2 Duo Proc E4500 (2.20GHz, 2MB L2 Cache, 800FSB)
Dell 19 inch Widescreen E198WFP Analog Flat Panel Monitor (w/ DVI)
1GB Dual Channel DDR2 SDRAM 667MHz - 2DIMMs
160GB Serial ATA Hard Drive (7200RPM) w/DataBurst Cache
Single Drive: 16X (DVD+/-RW) Burner Drive
Intel Graphics Media Accelerator 3100
Integrated 7.1 Channel Audio
10GB for 1yr Online Backup by Dell Datasafe
Windows XP Home or Vista Home Basic
1 Year Limited Hardware Warranty with Next Business Day On-Site Service