edit: when I was about 4 years old, I had a crown put on a tooth, so I couldn't drink any sugary sodas. But the woman who looked after me and other kids used to give me something called Diet Pepsi. Nasty shit! Ever since then, I've stayed away from diet sodas.
For more info, check out Excitotoxins: The Taste that Kills by Russell Blaylock. Interesting reading about food additives, including the original nasty, MSG (yep, "Chinese Food Syndrome" is real.)