coke zero
aspartame isn't that bad for you, you'd have to drink around 20 cans a day for any even remotely ill effects (mild headaches etc) , it's just made of two amino acids ( L-phenylalanine and L-aspartate )both of which are found in all proteins.
people who are worried about the ill effects of a can of diet soft drink or two must live in a hermetically sealed bubble of health cos your more likely to get ill from walking down the street.