What is a fair price for selling my desktop computer?

I'm looking to sell my desktop to get something newer and more portable. I built it in the summer of 2008. Below are all the parts I used:

• Kingston HyperX 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800
• LIAN LI PC-7B plus II Black Aluminum ATX Mid Tower Computer Case
• SAMSUNG 20X DVD±R DVD Burner with LightScribe
• Acer AL1916WAbd Black 19" 5ms Widescreen LCD Monitor
• Creative Sound Blaster X-Fi Xtreme Audio
• Linksys WMP54G 32bit PCI2.2 Wireless-G Adapter
• ASUS EN9600GSO MAGIC/HTDP/512M GeForce 9600 Video Card
• ASUS P5Q LGA 775 Intel P45 ATX Intel Motherboard
• OCZ GameXStream OCZ700GXSSLI 700W ATX12V Power Supply
• Intel Core 2 Duo E6750 Conroe 2.66GHz LGA 775 65W Dual-Core Processor
• Seagate Barracuda 250GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive
• Seagate Barracuda 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive

Does anyone know what would be a good asking price for this computer? Thanks!