I’ve been using Pixelmator for a few years now. I discovered it through a Macheist bundle and have since upgraded a few times. It’s an amazing graphics tool for most of day to day ‘shoping needs. One of the things I like the most about it is how it can very very easily scripted and referenced in Automator. So you can imagine how cropping and resizing product shots just got a lot easier.
By the way, this app is really cool.