I'm big on multiple backups myself. I use a program called SyncBackSE, which is a backup and file/directory synchronization program. I use it for my business, but it also works really well for photographic directories.
I have a standard data directory on my office/home raid storage system where everything resides. When I am headed out of town with my laptop I synchronize selected storage folders between my RAID system and the laptop. On the laptop I run another instance of the program and synchronize between the laptop and a 2 TB USB 3 drive. Once everything is in sync I can delete the camera cards.
New data is downloaded to the laptop. Once complete, I run SyncBack to synchronize the laptop drive to the USB 3 to provide redundancy. The program can also be set up to synchronize across an FTP connection, so that whenever there is reasonable internet bandwidth I can synchronize any changes to my in house FTP server, which utilizes a directory on my RAID storage server.
Soon I'm planning on some sort of windows 8 tablet or ultra convertible, such as the Surface Pro, or Lenovo Yoga, either with a 512 GB SSD drive. The back end synchronization with a USB 3 drive and a RAID storage server will remain the same.
Finally, I have two 12 TB 4-drive RAID servers that run an automatic backup mirror every night. They reside in two different areas of the building, off of separate power circuits for further data integrity.