Curious about sale value of my 2009 Mac Pro

I'm starting to think about selling my Mac Pro and replacing it with a mini since it seems that it may not be best suited for me. It was bought right at launch in March 2009. Could anyone suggest what kind of price I could ask for on ebay or kijiji etc.

2009 Mac Pro 4,1
2.93Ghz Quad core Nehalem
6GB RAM (3X2GB)
1X Superdrive
1X WD Caviar Blue 640GB (actually have 2X WD 640 Blacks, 1.5TB samsung and 240GB Intel 520 SSD. But going to use them in next computer)
1X Flashed Gigabyte 5870 OC 1GB (Way the heck quieter than the apple 4870 http://www.gigabyte.com/products/product-page.aspx?pid=3430#sp)
1X Apple OEM ATI 4870 512Mb (not installed but available as backup incase of issue with 5870)
OSX 10.6.8
Built-in Bluetooth and Wifi 802.11n
That OWC blue thingy to mount HD in 5.25 bay

The computer has 0 issues. The 5870 was not flashed by me, but works flawlessly in OSX and Windows 7, of couse with no boot screen unless connected via VGA. It is overclocked by the manufacturer (I think like 25Mhz) but when running windows I use MSI afterburner to down-clock it back to normal 5870. Currently using 2010 firmware to get audio over the HDMI, but would flash back to 2009 before selling to avoid possible problems.

It's really hard to get a real value by going off what others have sold for on ebay. Theres a 2.66 2009 Quad that sold for $500 and a 2.66 2X dual core (2006 is that?) that sold for $750, neither had any kind of significant upgrade. Then I see 2.26 8 core for $1600, but it's the base model. There's is no quad 2.93 with 5870 that I can find to judge the value. That site Mac2sell says it's worth $2500 without the gfx card (I find a little high) and then there's that other site Vsomething that says it's $300. There is no way in hell anyone is getting this for less than $1000, that would just be stupid. It's the same thing as the current pro with 2 less cores.