Photoshop crop has blurred/feathered edge
I have occasionally been having a problem in Photoshop where the edges of a cropped image are feathered by a couple of pixels. Not a big deal on images that are thousands of pixels on a side but it's a big problem when making 150x150px head shots for online profiles. This appears to happen when the crop starts at the edge of the image and the layer is unlocked (eg: not the Background layer). You can see the feathered edges at the bottom and right edges of this crop. Feather for the marquee tool is 0px and anti-alias is off if that matters since the Crop tool has no feather or anti-alias options.
This is Photoshop CS 5.5, but I recall having this problem on and off ever since we got transparent layers in Photoshop 4.
I suspect your crop boundaries are not snapped to pixels. Your crop tool should snap to pixels on the initial click and drag, but any modifications after that will not snap to pixels.
If there is a better way I'd love to know, but when I need pixel precision I create Guides (holding Shift while dragging) around the desired crop area. The crop tool will then be able to snap to the guides to give pixel perfect cropping.