CropGig for OS X ($2.99)

You just want to crop the photo, maybe resize it for your iPhone's background, or get it ready to post on your blog. You want something simple and quick. Quickgig's CropGig is your app. Crop, straighten, rotate, resize, or round the corners can all be done easily without the hassle. CropGig also provides an always on magnification view of the pixels the mouse is over so you can easily know where you should cut.

Immutation owners will get a code for this along with everything else that comes before PictureGig