Just yesterday bought the 3.4ghz 27" iMac, upgrading ram to 16 and purchased a WD My Book Studio 3TB FireWire 800 External Hard Drive for storage. My question is, what would be the best configuration for the HD with TimeMachine (never used TM) and using the HD for storage as well? My thoughts would be to partition the drive into three separate partitions or would two partitions be enough. Most of the storage would be for raw photo files. Would really appreciate the help. It has been over 20yrs since using a Mac.