I drink LOTS of diet soda. For me, drinking diet soda has been IMMENSELY helpful for losing weight because I used to drink just as much regular soda, and at least its zero calorie. Then again, for every can of soda I drink I probably drink 3 times that in water, so I never see the appetite issues other people have mentioned. I also don't drink coffee or tea so this is my source of caffeine, and I would NOT survive without it.
(I've also always be very skeptical of the people screaming from the rooftops about how bad diet soda is for your health--I blame years of Chem/bio courses and the realization that "CHEMICALS WILL KILL YOU" is a load of malarkey haha)
"I'm loyal to nothing...except the Dream."