Here is some info I found on Coke Zero. Now you can all rest tonight.
"...So what's so Zero about Coke Zero? Don't plain old Diet Coke and the rest already have zero calories? It's the taste. Basically, Coke Zero starts with the cola formula of Coke Classic and uses aspartame and acesulfame potassium as the sweetener instead of sugar. Sounds like a sure winner to me.
Diet Coke, the world's No. 1 diet cola, uses a formula more similar to New Coke which is really old forgotten Coke since they trash-canned New Coke nearly two decades ago.
Coke Zero has no bitter aftertaste that some drinkers find with diet colas. Some taste-testers noticed a distinctly cinnamon tinge to Coke Zero, but frankly, it tasted like a regular Coke to me.
Who is the target for Coke Zero? It's tough guys who need to drop a few pounds, but feel a little frilly drinking something with the word "diet" on the label.
Women have been grooving to Diet Coke for decades and won't budge. Diet Coke has an incredibly loyal fan base. And Diet Coke drinkers now prefer that taste to Coke Classic...."
http://www.chron.com/cs/CDA/ssistory.mpl/dining/drivethru/3235382