I now limit myself to 1 diet coke a day and have not had any problems since getting banded in Sept 09. Same with the beer, I used to drink it everynight but now limit myself to 5-6 bottles of Buds once a week when out for a meal with the DW or game of pool with the guys from work.
I know this will horrify a lot of banders who have been warned by thier doctors to avoid it. However, the team that carries out my surgery allows it, and told me that so long as I don't consume any more and limit the beer to once a week I will be fine. They are more worried about the calories in the beer than the gas and bubbles .
I am not trying to get anyone to go against the advice of their doctors which I believe they should always follow, but I think that for me, missing out on these treats for the rest of my life would have been one sacrifice too far.