Another vote for the Strawberry Sherbet/Vanilla Soft Serve swirl at the Enchanted Grove in Fantasyland.
I also love a tropical smoothie sold in Tomorrowland that's near, not Mickey's Star Traders, but the other main shop in that land. Can't remember the name of that shop or where I got the smoothie, but I know they sold ice cream too. I was sick as a dog with the flu (I had gotten sick 2 days earlier towards the end of the day at Epcot; may I just say traipsing around WDW with the flu is not easy, LOL) and that was the only thing that made me feel better.