EDIT: Good black coffee goes well with a lot of stuff actually. You just need to make it with a french press! Not too hot, just good and warm. It feels as though good coffee or something to drink when you smoke refreshes the palate, so you can taste the tobacco better. My thoughts on why this is would be that the coffee washes away the coating of tars, oils, and anything from the tobacco in your mouth and cleans the taste buds.
Maybe the soda's bubbles help remove the stuff from your mouth even better. All I know is Dr Pepper or Coke goes well with a pipe. Same with Sprite. Soda water doesn't really do it for me though.
Appearantly it's bad to smoke while you drink, for the tobacco and the alcohol pooling in your saliva can carry a lot of carcinogens and screw your mouth up. Then again I used to be a pretty heavy drinker and smoker, I still am a moderate smoker. I don't think sucking down Camel Wides with the filter torn off and homemade mule kick from a mason jar is the healthiest thing one can do, but I'm not dead. Either way I'm staying off booze.
~Levi