The CompactFlash pricing information is a little out of date. A spot check shows fairly even cost/storage over the 256MB-1GB range...1GB isn't the cutting edge of CF capacity anymore and no longer carries the cost premium.
Also, after dealing with a couple CF failures, I'm not so sure that a bigger card necessarily sets you up for a bigger data loss. The failures I've encountered affect some region of the card's memory which, obviously, affects anything the camera attempts to store there, but pictures elsewhere on the card can usually be retrieved with inexpensive software, even if the FAT filesystem is corrupt. A 4K failure is a 4K failure regardless of the CF card size.
Of course, there may be some CF failure modes I haven't encountered which render all data gibberish in which case the argument for a smaller card holds.
On a related note, and more of a question, how robust is JPEG2000 in the face of data corruption? If a 118 byte block in a file gets scrambled, in an uncompressed format you loose exactly that much data. With a compressed format the toll can be much greater as I understand it. How much greater with JPEG2000?