With the XD (which is what your camera uses), there are a few different versions that are used to take advantage of different functions. For instance, if you want to take panoramic pictures, then you want to have a particular type (H or M) of card. I'm not sure of all the options (I have a Kodak camera), but I believe that's what the different letter types are for. As for brands, anything is going to be fine, just make sure that the card you're buying isn't too big for the camera to be able to read... (Your manual will tell you the maximum card size...)