iMaginator, a low-cost image editor based on CoreImage
iMaginator is another CoreImage-based editing app in the tradition of LiveQuartz, but with one exception: it costs $49. I've used LiveQuartz a bit, and I haven't installed iMaginator yet, but from the screenshots its interface does look like it brings a few more features to the table. Over 108 filters and effects are available (though I don't know how many of those are supplied by CoreImage), you can create QuickTime movies of your images and you'll get free upgrades "for life" if you purchase the app.
If anyone beats me to playing with the demo, feel free to post your thoughts in the commentts.