For me, it used to be Oreo.

Now, it is Banana Creme Pie. God, I'll never get enough.

A while back, DQ introduced these "cheesequake" blizzards, which was various flavors plus cheesecake. There were two different DQs around us. One minced the cheesecake, wasn't good, you could barely notice the cheesecake. The other had the cheesecake in chunks. THAT was good. The strawberry cheesequake was my favorite Blizzard for a short while. Until that DQ also started mincing the cheesecake.

Before and after, my favorite blizzard was the pecan cluster. Had pecons (of course) as well as chocolate and/or caramel.

I remember those Cheesequakes. Rarely got 'em though.