After Leopard killed Photoshop 7, the need for a new image editor became even more important for me. It's been a toss up between Pixelmator and Acorn for me, and I think they both are both great applications. Pixelmator has a Photoshop feel to it, but Acorn has a different feel to it with its stripped down interface.

In the end, I finally went with Acorn due to Acorn's better shadow effects with text, it's lower overhead (it worked smoother with older computer), and Gus's excellent and timely support.