I have a simple process that may help. After each shoot, I take each 4GB card (I use SanDisk Extreme IV 4GB cards) and burn the RAW files to DVD immediately. This way I have a specific archive of each shoot in its entirety. Then I load up the images in Lightroom, sift out the keepers from the also-rans, and export as 16-bit TIFFs the ones I will edit/retouch. These files get backed up to my photo archive drive using Time Machine. This keeps my Lightroom catalog file size down, yet keep the integrity of the shoot intact. Hope this helps....