I recently purchased the MCE OptiBay and am going to add a Seagate Momentus 7200.4 500gig (BOOT DRIVE) to my Seagate 5200 500 gig (DATA DRIVE), already inside my MBP. I was reviewing macperformanceguide.com and was interested in formatting the new 7200.4 into my Primary Boot Drive with all my data on the other old 5200. My question is, What should my Boot Drive consist of? The OS and Applications or only the OS itself? Also I was looking to create a scrach partition... would this best on the boot drive or the data drive? Thanks for any help!