I prefer old fashioned cream soda but it's never found in restaurants and rarely found in stores so I get whenever I can. Second choice is Mountain Dew (regular or Baja Blast)
In the past I would have had no trouble chugging down then entire 2 liter bottle in a few hours but these days I've pretty much cut back to just once in a while. I don't have health issue but my family has diabetes history. These days I drink mostly real juices (not the water down shit loaded with sugar, 100% pure from fruits)