I was reading the Wikipedia entry on Diet Coke, and it said something about how some overseas versions of Diet Coke/Coke Light are sweetened with a type of sweetener known as cyclamate. Many people apparently claim that these versions taste better than the US formulation.
Cyclamates were apparently banned from the US in the 1970s after some tests showed it to cause certain health hazards, but many have refuted these claims. Indeed, these claims don't sound much worse than the ones that have floated around about aspartame.
I never knew about the existance of cyclamtes until recently, and I must say this interests me.