Although I've allowed myself a very occasional indulgence (maybe three times in the past year), I've given up on my old daily doses of regular soda. And when I do pick up diet, I make sure it's sweetened with splenda or stevia, but not aspartame (because aspartame gives me horrible migraines). I probably haven't even bought a case of diet soda since this past spring.
Soda was only an occasional treat as a kid, and remembering that helped me with my mindset when I decided to lay off. It most certainly can be done, and you'll feel better for it.
Something I do mess around with is Sodastream, although I add unsweetened cranberry juice to the water instead of syrup.
