Allright guys, I'm in the process of slowly upgrading my system to a Core i7 based configuration. What I basically need are several loose components -HDD, screen, videocard, soundcard and 5.1 surround system will all migrate to the new setup- so what now just need is a PSU capable of running an CrossFire setup, mobo with i7 support, the i7 itself, memory (3 or 6 GB) and if I really need to a case as I don't know if a P4 certified case has enough airflow to cool an i7 + CrossFire setup. I have been searching around a bit, is it wise to buy the stuff as cheap as possible through eBay or should I stick to safe and buy them new? Any shops that offer cheap i7 systems? What say ye all?