There are many versions of eggplant parmesan. I probably like them all. The earthy sweetness of the eggplant and tomato sauce, the gooey mozzarella, and the sharpness of the parmesan all come together to make something delectable. Eggplant parmesan was the most satisfying vegetarian dinner I ate when I was growing up.
In some recipes the eggplant is breaded and fried. While this adds a whole extra layer of texture, I don't think it's necessary. The version I grew up with was one my mom made and perhaps it's just the familiarity of it, but I really do think it's the best. Because it isn't fried it's not greasy which is often what happens with eggplant. A hearty filling entree I wouldn't dream of serving it without spaghetti on the side.