While on vacation one of my memory cards developed some sort of problem so I thought I'd lost about a hundred pictures of the mountains and a hike we took on Boxing Day. I tucked the memory card away and decided to try Photo Rescue
to see if it could recover the pictures. Two of the pictures were corrupted but the rest appear to have been recovered successfully. It also found some pictures from this summer (both LeConte and Wyoming) that had been deleted. I heartily endorse this product. (The demo won't actually recover pictures but it will show thumbnails of what it thinks it can recover.)
I like it when computers can fix problems instead of cause them.