If you're doing any sort of photo manipulation it's generally accepted that Photoshop is the program of choice. It's become an industry standard and as such is priced at a level that takes full advantage of it's monopoly. This is reasonably acceptable for businesses, but for the individual it's rather a lot of money to pay just to remove the wrinkles from Aunt Edna's picture. So Photoshop released Photoshop Elements, great! but when using it it always feels like a stripped down version of Photoshop, which is essentially what it is.
Along comes PixelMator. "Image editing for the rest of us" A universal Binary program for Mac OS X.
The first thing you notice is how good it looks, its got a sort of Aperture look with the main colour being black, all the panels float on the screen and they all have that slight transparency that gives the application a professional feel. The second thing you notice is how quick it runs, especially if you've got a meaty graphics card in your mac. PixelMator takes full advantage of Core Image meaning that most of the image processing is done on the image card leaving the main CPU to do other things (like render coverflow smoothly!).
Pixelmator supports over 100 file formats including PSDs with layers and has loads of the same functions as the full version of photoshop all for $59!
Check out the demo, it's well worth it.