A while back we tried every Mac recipe software we could find. We narrowed it down to MacGourmet for our use. Although, I seem to recall Yummy Soup being high on the list too.
MacGourmet has an optional meal planning module, does shopping lists, and syncs with the companion iPhone/iPod Touch application. We really like how easy it is to import recipes from Web sites by just dragging in the URL from your browser. It figures everything out and even brings in the picture if there is one. We also like how it can easily e-mail a recipe. And there’s a mode called “Chef View” that uses really large print so you can see it across the room.
They describe it as iTunes for recipes, which is probably a pretty good description.