The SD Card is a highly secure stamp-sized flash memory card. Jointly developed by Matsushita Electronic (best known for its Panasonic brand name products), SanDisk and Toshiba, the SD Card weighs approximately two grams. The SD Card can be used in a variety of digital products; digital music players, cellular phones, handheld PCs (HPCs), digital cameras, digital video camcorders, smart phones, car navigation systems and electronic books.
Strengths: Small, fast in digicams & reading/writing in a laptop.
Weaknesses: 256Mb was faulty, but was replaced by Sandisk for no charge. So far so good.
Bottom Line:
I've purchased both 512Mb and 256Mb Sandisk Ultra II SD cards. The 512Mb has been faultless however the 256Mb started deteriorating after 3-4 uses... unfortunately I did lose some pictures/video despite trying multiple card recovery software programs.