In a large bowl combine pudding mixes and milk. Mix on low until smooth. Add sour cream and blend. Add Cream Cheese and mix until smooth. Add Cool Whip slowly and blend well. Mix in Vanilla and set aside.
In a trifle bowl bowl, layer 1/3 of pudding mixture, half of sliced bananas; repeat layers. Top with last third of pudding mixture. Garnish with extra vanilla wafers if desired. Cover with plastic wrap and refrigerate until ready to serve.
I sometimes use a 9x13 dish instead of a deep bowl. In that case, I do alternating layers of vanilla wafers and bananas, ending with a layer of vanilla wafers. Pour the pudding mixture over the stacked layers and smooth with a spatula spreading into the spaces between the layered bananas and vanilla wafers. I garnish the sides of the dish with extra vanilla wafers and crumble crushed vanilla wafers over the top.
FAVORITE VARIATION: Use sliced strawberries instead of bananas. It is scrumptious!