Now that I have a good 4000 or so actuations on my 30D, I can say that half of the times I have taken my memory card out of the camera...........some or all of the pictures are corrupt. I have posted about this a few times, but since it hasn't happened the last 4-5 times I haven't done anything about it. I have been formatting the card via Windows after each use, and then I format with the camera. I took 500 pictures this past Saturday, and 515 this past Sunday..........didn't have one corrupted file. Today, I take the 100-400 out to take some pictures (since its the last day I can use it)......and I shoot about 50 pictures. The first 20 are corrupt. Here is the weird part...........I can see the pictures FINE when scrolling with the camera, but can't get any program to view it on my computer. Also when I am trying to DL the pictures, they prompt a windows error window about them being corrupt. Anyone have experience with this enough to rule out the camera, and point to the CF card?