A 4GB SanDisk Extreme III failed today. I've only had it for about 30 days. At about the 40 shot mark at Boo's Xmas dance class recital the D200 displayed the CHR error (bad card). Dropped in a spare 1gb card and carried on. I can't recover any data using SanDisk's recovery utility. The card will not reformat either on the PC, the Mac or the Camera. How often do these things fail? These cards are not the least expensive of their kind!