They're interested in anything I eat, of course, and they love, love, love canned food and those rolls from Natural Balance.
I feed Natural Balance dry food (the blue bag) right now. I fed Nutro Natural Choice and Eukanuba Natural before this (I guess I have a thing for foods labeled "natural"). They seemed to like Nutro and Eukanuba. Sadie's always been a pretty picky eater (and will get loose stool pretty easily), and I think Eukanuba was her favorite. I know there are issues with Iams (Eukanuba), though, so I don't really want to go back to it.
Not that my dogs look underfed, but I want them to like their food and not eat it because they are super hungry from not eating! That food thread that popped back up made me think about this. It's such a dog-specific thing... But also such a pain to figure out!