I'm going to be swapping cards around in my mining rigs to lower temps for the coming summer and I'm probably going to have an odd 5970 to sell.  I'm pretty sure its gonna be an XFX (I've got a few XFX and sapphire, I like to stay with 1 brand per rig).  Works great, mining BTC as we speak.  Right now used 5970s are going for $500 pretty reliably on ebay, and BTC is trading around $.80/1BTC so I'm looking for that range.  Any takers?