Probably just straight old-fashioned Coke or Pepsi (I can't tell the difference
)
We have a drink over here which is more popular in the North but I used to love as a kid, still like it occasionally, called Dandelion & Burdock. I suppose in a way it tastes a bit like liquid bubblegum (as someone once described it to me ) LOL .
If I want something harder, a good quality ginger beer, one with bite!!
There are only 2 I can honestly say i can't drink, Irn Bru (which I think is Scottish, or at least quite popular up there) , it's far too sweet for me, and i never liked Dr. Pepper.