I think it would be sweet to have a recipe box app for the iphone. I imagine being able to add recipes from online sites (allrecipes.com, etc.) as well as typing your own in obviously. Different templates for the recipe cards.
I think holding the iphone in landscape would show the "recipe box" as you would look down on it on the counter in your kitchen. you can touch the different "header tabs" to get to the different groups.
Pretend with something like this, but a little more realistic:
it could be kinda cool to be part of a kitchen suite, where you could pick out recipes for the week and it would figure up your grocery list for you. i can't think of other "kitchen apps" off the top of my head....oh wait...how about measurement converters??