Re: Is diet coke dangerous ?
To fully understand the risks involved in food consumption, you must first understand what cancer is. A really succinct description of cancer is that it is an accumulation of mutations in a cell-line's DNA that bypass enough checks to lead to uncontrolled growth.
Your cells are constantly exposed to mutagens (substances that cause mutations to DNA) ranging from hydroxyl radicals in water to UV rays from the sun. In terms of what you have control over, food hosts a wealth of radical-inducing agents. Practically everything you eat has the potential to create radicals, even the essential nutrient of metabolism, glucose, is dangerous to a cells since it has a free hydroxyl group that is capable of generating more free radicals (thus explaining the large amount of organ failure in uncontrolled diabetes).
With that being said, you must consider what you are putting into your body and weigh the health risks with how much you enjoy it. While aspartame is not natural and may carry a greater threat in terms of its radical generating ability, it may or may not be less dangerous than consuming large amounts of fructose in normal soda since it also can damage DNA by a similar mechanism.
Ultimately the question comes down to whether or not you want to give up soda and stop a behavior that has the potential of causing cancer, or if you want to enjoy soda and take the risk of possibly getting cancer. As an extreme case, I had a chemistry teacher who literally stopped eating for months because he was so scared of food radicals. He almost died of starvation and even now he is very thing and eats only home grown raw vegetables. In a way he is right since everything we eat, whether it be steak of cooked broccoli, can damage our DNA, but would an extra 10-20 years of cancer-free life be worth such a stringent diet to you? It is a personal question you need to make for yourself.
What you need to do is decide whether or not you accept the risk, then just live your life and stop worrying. Enjoy the time you have and try to spend it in ways you want to instead of worrying about how much more you might have left.