I'll second! At three years old, DS STILL loves applesauce and plain yogurt--it's the fall-back food when nothing else works. He also discovered yogurt with crushed pineapple. I've mixed in frozen blueberries as well.
i love making smoothies with yogurt. i add all kinds of different things, depending on the mood... bananas, berries, sometimes some orange or apple juice, sometimes some protein powder for an extra boost, anykind of fruit really, but especially juicy ones like mango, pineapple, papapya... blend and enjoy. we eat them for breakfast all the time, and also put them in popsicle molds in the freezer. yummy.
when eating it out of a smoothie - fruit or fruit preserves, or sprinkled with granola are my two faves. i also use it in place of sour cream when i'm making burritos and stuff like that, or as a base for dips to eat with cut up veggies.