Prices don't seem to have bottomed out as much as expected yet but certainly the Q6600 seems to be the CPU to buy (unless you care for a few more MHz on a dual core processor, bah):
http://techspot.pricegrabber.com/search_getprod.php/masterid=31693422/fd=1
http://techspot.pricegrabber.com/search_getprod.php/masterid=31693422/fd=1