I've always used somewhat small cards -- 2, 4, and 8 gigs, never anything bigger -- so that if a card dies I don't lose all the shots. This will change, however, when I get my 1D Mark III. With that camera, I intend to shoot RAW+Jpeg, storing all the RAWs on the CF card and all the Jpegs on the SD card. That way if either card fails, I've still got all the shots on the other card.
I've also considered one of those portable Epson backup devices. It won't be as important when I get my 1D 3, but it wouldn't hurt.
Large 16GB / 32GB
