Here's what Ward Stanke says, "Pixelmator was written for the Mac, and it has a more intuitive Mac-like interface than GIMP. I personally prefer it over GIMP or even Photoshop."
Pixelmator is a Photoshop-like picture editor. It has many, but not all, of the same features at a tenth of the cost. He points out that it's currently on sale for $14.99 (normally around $60.00, and this is for a limited time). The site does not say when the sale is over, but hurry, take a look.