Yes, by backing up to my local RAID array and then syncing with S3. I just figure it's not worth re-using the SD cards and they're an extra backup.

I actually figured out every photo I take has

  - one copy on the SD card
  - two mirrored copies on my raid
  - 3 copies on S3
  - 3 copies on flickr (I believe)

for a total of 9!