I just upgraded so I am getting ready to put my 20" iMac up for sale. It's a mid-2007 model with 2.4 C2D, 500GB HD and 4Gb RAM. Original box and everything. How much is a fair asking price? I was thinking starting it at $700 or is that too high? I checked ebay listings and they are priced similar but no bids. Anyone else sell one of these recently? What's a realistic selling price?