For what its worth, there isnt really too much of an issue buying refurb , if you do just chnage the hard drive and the fans..always get NEW drives... but CPUs once they work.. they rarely fail, as such you can save huge amounts of money by using this route
e.g. I build my own systems or buy refurb shells.. I buy my CPU always as seconds at around half price and I will search around for X-Demo units with monitors.
Hope thats helpful